DIPARTIMENTO DI
FILOLOGIA, LETTERATURA E LINGUISTICA
CORSO DI LAUREA MAGISTRALE IN
Linguistica e Traduzione: curriculum Linguistica
TESI DI LAUREA MAGISTRALE
A Constructionist Approach to Multilingualism in First Language
Acquisition: An Analysis of Grammatical Organization in Bilingual
Italian/English Children during the Critical Period
CANDIDATA
RELATORE
Leigh Anne Benzaia
Chiar.mo Prof. Domenica Romagno
CONTRORELATORE
Chiar.mo Prof. Alessandro Lenci
INDEX
Abstract 5
Introduction 6
Part I: Neuroplasticity and Critical Periods for Language Acquisition 9
1.1. Overview 9
1.2 Critical periods in the body: The auditory and visual systems 16
1.3 Critical periods for language acquisition 23
Part II. A Constructionist Approach to Language Acquisition 31
2.1 A theoretical framework for first language acquisition 31 2.2 Language is learned: Statistical learning and word segmentation 45 2.3 Statistical pre-emption: How children learn productivity 55
Part III. Constructions in Multilingual First Language Acquisition, Crosslinguistic Influence
and Evidence from Diary Studies 59
3.1 Simultaneous bilingualism and evidence for the development of differentiated language
systems from the beginning 59
3.2 Personal data of children in the diary studies 66
3.3 Negative transfer in bilingual Italian/English children due to crosslinguistic influence 69 3.4 Early constructions in bilingual Italian/English children: Evidence from diary studies 78
Part IV. Empirical Study: Acceptability Test of Divergent Constructions in Bilingual, English/ Italian, Elementary School-Aged Children During the Critical Period 90
4.1 Color the car red: Presentation and analysis of divergent constructions in English and
Italian 90
4.2 Acceptability test of divergent constructions in English and Italian in bilingual children 98
Results 106
Summary and discussion 109
Conclusion 113
Bibliography 114
Appendix A - Additional Data from Diary Studies 122 Appendix B - Additional Data from the Acceptability Test 123
Acknowledgements
I wish to thank Professor Domenica Romagno for her steadfast support in all aspects of my graduate thesis and beyond. Her words of encouragement, spoken in a lecture hall on a cold day in March 2019, one month before the birth of my third daughter, will forever represent a turning point in my future in Linguistics.
I likewise extend my gratitude to Professor Alessandro Lenci for his time, his patience, his truly international approach to education and most of all for his introduction into the world of
A Constructionist Approach to Multilingualism in First
Language Acquisition: An Analysis of Grammatical
Organization in Bilingual Italian/English Children
during the Critical Period
Abstract
Through the analysis of neuroplasticity and critical periods for language acquisition due to prolonged prefrontal immaturity, brain malleability as a result of linguistically-enriched environments, i.e. bilingual and multilingual settings, is explored. Furthermore, the two major approaches in first language acquisition, the nativist approach and the usage-based, constructionist approach are investigated and a case is made that native languages are acquired through the processes of statistical learning combined with cognitive abilities, social skills, a tendency to imitate and vast linguistic input from mothers to their children. Furthermore, diary studies involving the author and her bilingual children are presented, negative transfer due to crosslinguistic influence is investigated and bilingual error fossilization due to sibling influence is hypothesized. Moreover, metalinguistic awareness of divergent constructions in English and Italian is investigated through an acceptability test administered to twenty-one Italian/English, elementary school-aged children during the critical period for language acquisition.
Introduction
The ability to process and produce natural language is undoubtably a human being’s most
miraculous cognitive function. Linguists and parents alike find little else more thrilling and sentient than a child’s first isolated words and the rapid progression of that child's increasing skill in
negotiating, explaining and entertaining with language during the first years of life. However, is linguistic knowledge innate in human beings, i.e. are children born expecting to encounter nouns and verbs, or are first languages actually learned? Through increasing knowledge of early learning processes and greater access to linguistic input from mothers to their children, the nativist approach to language acquisition is progressively being challenged by a usage-based, constructionist
approach.
Neural and behavioral studies show that exposure to language in the first years of life influences the brain’s neural circuitry even before infants begin to utter their first isolated words. The human brain possesses astonishing properties of plasticity which aid in the processes of learning and in certain cases, recuperation or even repair following damage. The prefrontal cortex is vital to the regulation of thought and the controlling of behavior and its slow development in humans leads to
consequential deficits in cognitive control. Cognitive control is the mind's ability to actively represent information which guides behavior; it is what allows for the selection of appropriate behavior and for the rejection of behaviors deemed inappropriate. Furthermore, cognitive control is at the center of self-awareness, consciousness and willpower.
Although lack of cognitive control may appear unfavorable, recent research has shown that
processes of conventional learning, such as the learning of language, delayed prefrontal
development and consequently less cognitive control in children may aid in the process of first language acquisition. Hence children are capable of acquiring multiple languages with relative ease while adults find the same task exceedingly more difficult. It follows that the supposition of a critical period for language learning is strongly supported by an extended period of prefrontal cortex development in children.
Any attempt to investigate the processes through which children in the critical period acquire their native languages must find its roots within a theory of grammar. In the theoretical framework of Construction Grammar, all elements of language are thought of as conventionalized pairings of form and function. Constructionist approaches attempt to answer questions such as how language is learned, how it is processed and represented and to explain the relationship between form and meaning. Multilingual first language acquisition and bilingual infants provide fertile ground for the trying and testing of constructionist theories on first language acquisition, e.g. statistical learning, general purpose verbs, word segmentation and statistical pre-emption. Furthermore constructionist approaches allow for the analyzing of divergent constructions in structurally diverse languages, such as Germanic and Romance languages, and the investigation of the ‘tolerance’ of creative and unusual syntactic constructions by their speakers.
This brief volume attempts to bring together areas of study which investigate how children learn this first language: e.g. early brain development and critical periods, first language acquisition in bilinguals through the analysis of negative transfer and error fossilization, and ‘tolerance’ of
divergent constructions in bilingual children during the critical period through an acceptability test. Through the defense of a constructionist, usage-based theory for first language acquisition, the presentation of evidence from diary studies of bilingual, Italian/English children and the analysis of
results from an acceptability test of divergent constructions in Italian and English, the following pages attempt to shed light on the miraculous process of multilingual language acquisition in children during their very first encounters with the gift of human language.
Part I: Neuroplasticity and Critical Periods for
Language Acquisition
1.1. Overview
World renowned neuroscientists Alessandro Sale, Nicoletta Berardi, and Lamberto Maffei define neural plasticity as “the capacity of neurons and of neural circuits in the brain to change,
structurally and functionally, in response to experience” (Maffei et al., 2014, p. 189).
Inherent in the word plasticity itself are the notions of pliability and malleability, and when such considerations are applied to the human brain, a multitude of possibilities, both theoretical and empirical, present themselves. Brain elasticity is indeed essential to the adaptability of human behavior as it constitutes a fundamental part of the processes pertaining to learning and to memory. It furthermore aids in cerebral development and in certain cases, recuperation or even repair
following damage from injury or stroke.
Miraculously, injury to the brain in children, e.g. damage from peri-natal stroke, and similar trauma in adults due to stroke or traumatic brain injury may be lessened and in some cases reversed due to properties of neuroplasticity. Ischemic and hemorrhagic strokes, both in children and adults, lead to cell death and are caused by insufficient blood flow to the brain. Such disturbances may result in the death of cells, damage caused by reactive oxygen species or inflammation, as well as the formation of gliotic scars. Glial scar formation or gliosis is a reactive cellular process involving astrogliosis, or an abnormal increase in the number of astrocytes due to the destruction of nearby neurons, a
process which occurs as a result of damage to the central nervous system. As with scarring in other organs and tissues, a glial scar is the body's mechanism to protect and begin the healing process. The formation of glial scars has been shown to have both beneficial as well as detrimental effects, in the case of the former, neural plasticity proves propitious towards improving specific functions,
however this occurs only once the acute phase has subsided and the lesion has been sealed (Huttenlocher, 2002).
Studies carried out on rodent brain specimens have demonstrated both the beneficial and
detrimental effects of reactive gliosis following injury. During the acute phase of disease, glial scars play an important role in insulating the locus of the lesion and also aids in remodeling brain tissue. Furthermore, glial scars assist in keeping the body’s natural immune response at bay, so as to restrict further damage and create a barrier which inhibits ulterior microbial infections and the diffusion of cellular damage (Rolls et al., 2009). Additionally, glial scars stimulate the
re-vascularization of capillaries which in turn augment nutritional, trophic and metabolic support to the nervous tissue.
Conversely, glial scars may act as a deterrent to axon regeneration and hence prevent immediate recovery of central nervous systems function during the chronic phase of disease, this is due to reactive astrocytes recreating growth-inhibitory molecules that inhibit axonal extensions.
Furthermore, the membrane of the scar serves as an additional barrier which prevents regenerating axons from crossing the lesion (Huang et al., 2014). According to Huang et al. (2014), reactive gliosis and glial scar formation in the human brain after ischemic injury behave similarly to those in animal models of stroke and thus the beneficial effects of reactive gliosis may also be posited in humans (Huang et al., 2014).
Neuroplasticity aids recovery in brain damaged infants and positively affects early language development: the case of peri-natal stroke
Brain damage in children has different implications for language development than similar damage in adults due to early neuroplasticity. Sadly, ischemic peri-natal stroke (IPS) is not uncommon in the population and occurs with an estimated of 1:1500 to 1:4000 live births (AHA/ASA, 2012). Hence, the prevalence of IPS is comparable to that of adult-onset stroke, making it an important area for research, particularly when considering the implications that such disease may have on language acquisition. In a groundbreaking study, Trauner et al. (2013) investigated early markers of language and gesture at 12 and 24 months in children who had peri-natal right hemisphere (RH) or left hemisphere (LH) stroke and contrasted their results with normally developing children.
Through their study, Trauner et al. (2013) investigated the language development of a very large group of children, namely one hundred and ninety-seven infants and toddlers, ages 10 to 25 months; this included seventy-one children with peri-natal stroke and one hundred and twenty-six normally developing participants. Given the young age of the children, the researchers asked parents to complete the MacArthur-Bates Communicative Development Inventory (CDI): Words & Gestures at a 12 month data point, or the CDI: Words & Sentences at a 24 month data point. Statistical
information was gathered regarding the percentile scores through the employment of a variance technique.
The researchers found no difference at 12 months across groups regarding ‘words understood’ ‘phrases understood’ and ‘words produced’. This trajectory changed for both lesion groups at twenty-four months, with the injured children scoring significantly lower than controls on ‘word production’, ‘irregular words’, and ‘mean length of sentences’. In longitudinal subset of
participants, expressive vocabulary failed to progress as expected from 12 to 24 months in the stroke group, with no differences based on lesion side. Interestingly, the researchers found that gesture and word production were dissociated in left hemisphere subjects. Based on their findings, Trauner et al. (2013) posit that early language development after peri-natal stroke follows a
different path from that of typical language development, and that this discrepancy may reflect brain reorganization due to neuroplasticity (Trauner et al, 2013).
Within the greater context of neuroplasticity and early language development, Trauner et al’s (2013) study provides several important insights. Firstly, the researchers have shown that early indicators of language development in infants and toddlers with unilateral brain damage exhibit a different pattern from what might be expected if the brain were innately ‘programed’ for left-hemisphere dominance for language at birth. In other words, the findings suggest that early language ability does not vary among lesion groups or normally developing children. However, by 2 years of age, both lesion groups exhibit significant delays in language production compared with controls. Hence, neither the earliest language indicators (at 12 months) nor the side of the lesion predicted the
trajectory of language development in children with unilateral brain damage. This differs greatly from the adult model of language in which the left hemisphere is vitally important for the upkeep of normal language function in most individuals, as adults with left hemisphere stroke are likely to suffer from some variety of aphasia.
In perhaps the most fascinating aspect of their study, Trauner et al. (2013) discovered that language appears to “stall” by the second year of life in brain damaged infants. As their results show, ‘words produced’ at 12 months do not compare to ‘words produced’ at 24 months in both brain damaged groups, a finding which implicates a ‘drop-off’ from the expected course of development. The researchers posit an astonishing example of early neuroplasticy and its affects on language
development in children in the following manner: despite early injury, the brain develops alternate patterns of neural connectivity, as it has not yet developed connections robust enough to handle the language burst that typically occurs at the age of the children in the study. Furthermore the
researchers hypothesize that following a period of ‘stalling’, it is possible that the language burst may occur later in brain damaged groups than in typically developing children. As a result, there may not be a rapid period of productive language development, but rather a slower course of progression as alternate connections are developed (Trauner et al, 2013). Hence, as will be suggested in the following chapters, an early language delay may actually prove beneficial to the developing brain.
Revisiting the aforementioned definition of neuroplsticity, the question is begged: how does life experience translate into brain malleability? Similarly to other mechanism pertaining to learning, such as first language acquisition, the answer lies in patterning: that which is cultivated through human actuality is transformed into patterns of electrical activity within neural circuits, and it is these very patterns which drive various forms of functional and structural plasticity. Specific cellular and molecular components concur both spatially and temporally to aid in this process, thus setting the stage for both the physical and occupational modification of the brain (Maffei et al., 2014).
Structural versus functional plasticity
Interestingly, it is posited that neural plasticity may involve modifications to the efficiency of already existing synaptic contacts, the formation of new synaptic contacts and or the elimination of those no longer in use (Maffei et al., 2014). Hence it is thought that they may contribute to
widespread changes in dendritic or axonal arborization, or rather, the terminal branching of nerve fibers or blood vessels into a treelike pattern, and may also promote the creation of neuromodulators or neurohormones. Neurohormones, hormones which are released by neuroendocrine cells into the blood, assume the role of neurotransmitters, taking on the function of autocrine or paracrine
messengers within the nervous system, thus transmitting signals to various parts of the body (Purves et al., 2001).
Neural malleability may be subdivided into two general types: structural and functional plasticity. Structural plasticity refers to the brain's ability to change its neuronal connections, hence modifying its physical structure as novel neurons are continuously produced and integrated into the central nervous system throughout the human life span. Transformations in the proportion of grey matter, or the areas of the brain containing the majority of neuronal cell bodies and the expanse involved in muscle control and speech coupled with synaptic potential in the brain constitute the most notable examples of structural plasticity (Mateos-Aparicio & Rodríguez-Moreno, 2019).
Conversely, functional plasticity exemplifies the brain’s ability to alter and conform the
occupational properties of neurons. Such modification may occur in response to preceding activity, through the cultivation of mnemonic capabilities, or in response to the damage of neurons
themselves, in which case it is denominated activity-dependent plasticity, or it may be due to the process of cerebral compensation following a pathological event, and is therefore referred to as
reactive plasticity. Reactive plasticity instead involves the transferring of functions from one area of the brain to another as a recovery response, to aid both in physiological as well as behavioral
1.2 Critical periods in the body: The auditory and visual systems
The Auditory System
A vital contributor to the realization of human language is the auditory system, a matrix whose development takes place within the context of neuroplasticity and more specifically within a critical period. The potential for anatomical and functional modification within the central auditory nervous system is defined as auditory neuroplasticity and indicates a specific time span during the first years of life when responses to stimuli and ambient noises are gradually created and established. Though it is quite redundant to expound on the crucial role that the auditory system plays in language processing and production, it is of relevance to briefly illustrate how sounds are transmitted to the auditory nerve and thus to the brain.
The auditory system is comprised of two main components: the peripheral system, which includes the outer ear, the middle ear, inner ear and auditory nerve, and the central system, made up of auditory pathways in the brain stem and the auditory cortex. The peripheral auditory system permits the transmission of sound from the auricle, or outer ear, to neurons within the auditory nerve. The outer ear houses the external auditory canal whose primary function is to capture sound waves and transmit them to the eardrum.
The middle ear encompasses the eardrum, the malleus, incus and stapes ossicles as well as the eustachian tube. It is connected to the outer ear by way of the ear drum and to the inner ear through the round and oval windows. When a sounds wave is transmitted through the external auditory canal, the eardrum begins to vibrate. These vibrations are sent through the ossicles and into the malleus, whose handle like structure then strikes the incus, which in turn moves the stapes. The
stapes transmits the vibrations to the inner ear through the oval window. In a miraculous display of ingenuity, the middle ear is also capable of protecting the inner ear. Should the ear be exposed to a dangerous excess of ambient noise, the stapedius muscle will contract to reduce the vibration of the stapes, thus shielding the inner ear from damage. This protective mechanism is known as the acoustic or stapedius reflex. Finally, the middle ear houses the Eustachian tube, which serves to balance pressure on either sides of the eardrum.
Within the inner ear the vestibule and cochlea are found: the vestibule governs balance while the cochlea is responsible for the overall experience of hearing sound. The cochlea is a spiral formation which houses the organ of Corti, an organ which contains a number of cilia present in a liquid denominated perilymph fluid. When the ossicles of the middle ear transmit vibrations to this liquid, the agitation causes the cilia to move, thus activating an impulse which is sent to the brain through the auditory nerve.
The central auditory system is the matrix responsible for interpreting auditory information through allowing sound to be transmitted from the neurons of the auditory nerve to the brain. This structure communicates with the peripheral auditory system by way of both afferent nerve fibers, which run from the organ of Corti to the auditory cortex as well as through efferent nerve fibers, whose path runs in the opposite direction. The cells present in the organ of Corti are subdivided into external and internal cilia and are connected to fibers which make up the two auditory nerves. Information from the auditory nerve is transmitted to the brain through several structures in the brain stem: the cochlear nuclei, the superior olivary complex, the lateral lemniscus, the inferior colliculus and the medial geniculate body. Quite remarkably, in addition to transmitting sound information, the auditory pathways also provide information regarding sound frequency, volume and location in space.
A most remarkable feature of the auditory system’s means of communicating with the brain are the spiral ganglion; a group of neuron cell bodies housed within the central axis of the cochlea. These bipolar neurons, or neurons which have two extensions, one axon and one dendrite, are the first neurons in the auditory system to fire an action potential, and provide the aggregate of the brain's auditory input.
The manner in which spiral ganglion neurons are able to accurately capture and encode the features of each complex sound stimulus is quite mysterious. As previously noted, hair cells and neurons in the cochlea are spatially organized according to sound frequency along the spiral of the cochlea. Hair cells located at the wider basal portion of the cochlea detect high frequency sounds, while those located at the apex of the cochlea detect low frequency sounds. Similarly, the position of spiral ganglion neurons along the tonotopic axis of the cochlea correlates with the frequency of input each neuron receives (Appler & Goodrich, 2011).
Auditory Neuroplasticity
As previously stated, the auditory system reaches it full potential in a very short window of time which occurs during the first years of life. This striking example of anatomical and functional modification constitutes the period in which responses to stimuli and noises from the environment are established and the stage is set for the untangling of human speech from what William James in his 1890 volume Principles of Psychology, called “one great blooming, buzzing confusion” (James 1890, p. 448).
Roughly until the age of four, a myriad of neuronal connections are present in the cortical areas that encompass the auditory system, thus leading to its rather accelerated development. However, after this period of rapid growth, the neurons involved in the mechanism of hearing experience
“pruning”, a process in which neurons and synapses which have not yet been activated are eliminated from the auditory system (Sanes & Woolley, 2011).
Synaptic Pruning
Synaptic pruning is a natural process that occurs in the brain between early childhood and
adulthood. During synaptic pruning, the brain eliminates extra synapses, structures in the brain that allows neurons to transmit an electrical or chemical signal to other neurons. It is believed that synaptic pruning is the brain’s strategy of removing pathways that are no longer needed, and that it is in essence, the organism’s strategy for maintaining more efficient brain function throughout the aging process as well as when new, complex information is acquired.
During infancy, the brain experiences an exponential amount of growth. Through a process called synaptogenesis, an explosion of synaptic formation occurs between neurons during early brain development. This rapid period of synaptogenesis plays a vital role in learning, memory formation, and adaptation to the world early in life. At approximately two to four years of age, the number of synapses hits a peak level and thereafter the brain begins to remove synapses which it no longer needs.
It is important to note that once synapses in the brain are formed, they may be strengthened through stimulation, or they may be neglected through lack of stimulation and ultimately eliminated from the brain through the process of pruning. It is posited that early synaptic pruning is largely
influenced by genetic endowment however it is encouraging to note that during the later stages of life, exposure to various types of stimuli help reinforce the remaining synapses. Hence it may be hypothesized that exposing a growing child to stimuli will cause his or her brain to develop and retain a greater number of synapses in the auditory system and that those synapses may be reinforced later on in life through exposure to enriched environments, i.e. exposure to music, participating in conversation with others and avoiding isolation. It follows that the exposure of infants to music in the first months of life may improve their ability to distinguish speech from other ambient noise and would likely benefit the aging population as well (Strait et al., 2012; Sanes & Woolley, 2011).
Although plasticity due to experience is far greater in the early years, it is known that the auditory system retains some malleability throughout life. Sharma et al. (2012) hypothesize that there is a difference between what is known as a critical period and a sensitive period. According to Sharma (2012), the critical period ends suddenly, after which the neural system is unable to adapt to further
stimuli, however, the sensitive period extends for a longer period of time, thus it represents a sort of second chance for sound to be introduced into the auditory cortex and promote normal
age-appropriate development (Sharma et al., 2012).
Neuroplasticity and the visual system
The visual system comprises the eye and the area of the central nervous system which gives organisms the ability to process sight as well as enabling the formation of several non-image photo response functions. It detects and interprets information from visible light, i.e. wavelengths which are visible to a specific species thus allowing them to create a ‘mental representation’ of their surrounding environment. The visual system carries out a number of complex tasks, including the reception of light and the formation of monocular representations, the neural mechanisms
underlying stereo vision, the identification and categorization of visual objects, assessing distances to and between objects, motion perception, guiding body movements in relation to objects seen as well as the perception of color.
Within the context of the development of the visual system, several critical periods for different visual functions exist. Functions which are processed at higher anatomical levels have a later critical period than functions processed at lower biological levels, that is, more refined visual functions develop over a longer period of time (Daw, 1998). It follows that treatment for
abnormalities in the visual system must be undertaken within the appropriate developmental critical period, so as to properly correct the problem before maturation is complete.
For instance, amblyopia, or lazy eye is a common sight disorder in which the brain fails to process input from one eye and increasingly favors the other eye. Though it is the most common cause of
decreased vision in children and is highly correctable if intervention occurs within the correct critical period, if left untreated or treated too late in development, it may result in permanently decreased vision (Maconachie & Gottlob, 2015). Daw (1998) warns, however, that “This general principle suggests that treatments for amblyopia should be followed in a logical sequence, with treatment for each visual function to be started before its critical period is over. However, critical periods for some visual functions, such as stereopsis, are not yet fully determined, and the optimal treatment is, therefore, unknown. (Daw, 1998, p. 502)
Daw (1998) identifies three main periods of development in visual acuity and the evolution of ocular dominance. From age 3 to age 5, young children develop acuity which begins at less than twenty-twenty and arrives at nearly twenty-twenty. During this critical period, acuity may be reduced by the various forms of amblyopia and fail to reach its full potential. Subsequently, a critical period ranging from the age of 3 months to 7 or 8 years of age occurs, during which
deprivation is effective in causing amblyopia, namely strabismus or anisometropia. Finally, the third critical period is represented by the time during which recovery from amblyopia may be obtained, e.g. time of deprivation to the teenaged years or even into the adult years. Daw (1998) notes that a similar subdivision of critical periods is found in the study of ocular dominance in animals. Nerve fibers in the visual cortex segregate into left and right eye stripes between birth and 6 weeks of age in the macaque monkey (Daw, 1998).
1.3 Critical periods for language acquisition
One of the most widely-held beliefs, both among linguistics as well as the general public, is that the ability to learn languages is confined to a particular time frame or critical period. The basic premise for this hypothesis is that first and second language acquisition are constrained by maturational changes in the organism, and that certain windows are better suited to language learning than others. The critical period hypothesis (CPH) remains at the center of a decades-long debate within the fields of linguistics and psychology, primarily pertaining to the extent to which the ability to acquire a language is fundamentally linked to age. CPH was first proposed by Canadian neurologist Wilder Penfield in collaboration with Lamar Roberts in their 1959 work, Speech and Brain
Mechanisms; it was subsequently popularized by Eric Lennenberg in his 1967 volume, Biological Foundations of Language (Penfield & Roberts, 1959; Lennenberg, 1967).
Empirical evidence for critical periods emerged principally from research investigating the language or ‘non-language’ of individuals who were deprived of linguistic input from birth until puberty. A heartbreaking example of almost total lack of language development is the case of Genie (Curtiss, 1977); a child who suffered unspeakable abuse at the hands of her father and lived
predominantly in isolation until she was rescued at the age of 13, or at the time of puberty. Though Genie was rehabilitated through rigorous speech therapy and continued to learn and use new language skills throughout her teenage years, she ultimately remained unable to fully acquire a first language (Curtiss, 1977).
Based on empirical evidence provided by the tragic case of Genie (Curtiss, 1997), preliminary research into the critical period hypothesis investigated brain lateralization as a possible neurological cause for language learning ability to diminish after the age of puberty, as it was thought that brain lateralization was completed approximately at the age of 13. Brain lateralization, or the ‘lateralization of brain function’ refers to the tendency of certain neural functions or cognitive processes to be specialized within one side of the brain or the other. The medial longitudinal fissure divides the brain into two distinct cerebral hemispheres, connected by the corpus callosum.
Although the macrostructure of the two hemispheres appears to be almost identical, different compositions of neuronal networks allow for specialized function that is different in each hemisphere.
As Maffei (2018) notes, though brain plasticity allows for the reorganization of many cognitive functions after injury or deprivation, language function such as grammar and lexical development are most often lateralized to the left hemisphere, particularly in right-handed individuals. Not surprisingly the areas of Broca and Wernicke are located in the left cerebral hemisphere in approximately ninety-five percent of right-handers and seventy-percent of left-handers (Maffei, 2018).
Based on the left hemisphere’s general specialization for language function, both psychologists and linguistics posited that Genie’s inability to fully acquire a language was due to lack of input and depravation which occurred during a critical ‘window’ in which the child’s brain allocated specific cognitive functions to either the left or right hemisphere, however this theoretical cause was largely discredited as lateralization does not necessarily increase with age, and no definitive link between language learning ability and lateralization has ever been determined (Archibald & Libben 1995).
Recently, it has been suggested that if a critical period does exist, it may be due at least partially to the delayed development of the prefrontal cortex in humans.
Researchers have suggested that prolonged development of the prefrontal cortex (PFC) and an associated delay in the development of cognitive control may facilitate conventional learning, allowing infants to learn language far more easily than cognitively mature adults and older children. The prefrontal cortex determines the brain’s ability to regulate thought and control behavior and the development of the human cerebral cortex is characterized by an extended period of maturation during which young children exhibit evident deficits in cognitive control. This pattern of prefrontal development is unique to humans among similar mammalian and primate species, and may explain why humans, and not chimpanzees, are such accomplished language learners (Thompson-Shill et al., 2009).
As is widely understood, humans, similarly to other primates, are born with an immature brain. In accordance with previously presented information, after birth, the cerebral cortex experiences a massive proliferation of synapses during the process of synaptogenesis, followed by a prolonged period of synaptic pruning. In primates such as the Rhesus Macaque, these developmental processes occur at the same rate in all cortical areas (Rakic et al. 1986). Conversely, the human brain exhibits a different developmental pattern. In humans, synaptogenesis reaches its peak in the visual and auditory cortexes within a few months after birth, however, the increase in the number of synaptic junctions in the PFC occurs over a much more prolonged period of time (Huttenlocher &
Dabholkar, 1997). Hence, the synaptic density of human PFC does not match that of the auditory cortex until children have reached the fourth year of life.
In contrast with researches who deem prolonged PFC development detrimental to human
development, as it results in delayed cognitive control, Thompson-Shill et al. (2009) highlight the positive effects of such prolonged development and posit that prefrontal immaturity may prove beneficial to language learning. The prefrontal cortex is the last part of the human brain to develop and is the area which is thought to regulate thoughts and behaviors. While past research has focused on the negative consequences of this developmental trajectory, Thompson-Shill et al. (2009) suggest that cognitive control impedes convention learning and state that “delayed prefrontal maturation is a necessary adaptation for human learning of social and linguistic conventions” (Thompson-Shill et al., 2009, p. 260).
It is evident that late prefrontal development has negative consequences on childhood conduct as it affects one’s ability to distinguish between appropriate and inappropriate behavior. Nevertheless, in activities of patterned learning, lack of cognitive control is thought to aid a child in the process of maximization, or rather, the consistent selection of the most frequent outcome based on the evidence with which they are presented. Conversely adults, in whom the PFC is fully developed, when faced with the same probability learning tasks make ample use of probability matching, or guessing. In other words, resolving conflict between possible responses in patterned learning requires the type of flexible thinking of which adults, and not children are capable. Thompson-Shill et al. (2009) state “To optimize performance, PFC functions as a dynamic filter, selectively
maintaining task-relevant information and discarding task-irrelevant information”, (Thompson-Shill et al., 2009, p. 261).
Interestingly, the researchers question whether there may be instances in which ‘inflexible’ thinking may benefit the learning process. Thompson-Shill et al. (2009) posit that the process of language acquisition, which includes the ability to thrive socially, to master cultural and linguistic
conventions and to extract the ‘right’ meaning from the ‘right’ context is hindered by an adult’s ability to think ‘unconventionally’ or ‘flexibly’. The researchers state that the consequences of conventional versus flexible thinking have been computationally demonstrated for the acquisition of irregular plurals in nouns, e.g. mice or deer as opposed to shoes or dresses; a set of linguistic
conventions adults find particularly difficult to master. They state “The trajectory of learning of these exceptions is non-monotonic in children, marked by a brief period in which
over-regularization errors (e.g., “mouses”) replace previously correct plural forms”, Thompson-Shill et al., 2009, p. 261).
Fast-forwarding to current research on critical periods for second language acquisition, of relevance is a recent study by Hartshorne et al. (2018) in which the researchers identified a ‘sharply-defined critical period’ for grammar learning, and a steady decline thereafter, based on a very large dataset, e.g. reports from 2/3 million English Speakers. Obtaining information from such a large group of learners allowed the researchers to separate critical-period effects from non-age factors, e.g., amount of experience which might affect grammatical performance. Hartshorne et al. (2018) were able to provide the first direct estimate of how grammar-learning ability changes with age, finding that it is preserved longer than was once thought, (e.g. until puberty) to the age of approximately 17.4 years (Hartshorne et al., 2018). Lending evidence to this supposition, current neurobiological research has shown that critical periods affect the neurological substrate for language processing, specifically for grammar (Wartenburger et. al, 2003).
Critical periods in multilingual language acquisition
Concerning the existence of a critical period in bilinguals, researchers remain divided; several scholars deny that critical periods constrain language acquisition (Bialystok & Kroll, 2018) and others adhere to the supposition that multilingual language acquisition is subject to critical period effects (Meisel, 2013, p.71).
Though it is true that simultaneous bilinguals, i.e. those learning two languages from birth, do indeed yield better linguistic skills than successive bilinguals, i.e. those who become bilingual later on in life, individuals with early onsets of acquisition of a particular language are typically also younger when they learn the language and thus experience a longer time of exposure than individuals with a later onset of acquisition. In light of these potentially conflicting factors, supposed critical period effects may be open to alternative interpretations.
Surprisingly, recent evidence for critical periods comes from research on sign language acquisition. Mayberry & Kluender, (2018) provide a different perspective on the CPH by investigating the specific learning circumstances unique to deaf children learning sign language, hence offering a unique opportunity to distinguish genuine critical-period effects from non-age factors affecting linguistic performance. In their landmark study, Mayberry and Kluender (2018) compared linguistic outcomes of the acquisition of sign languages in childhood L2 learners with that of
post-childhood L1 learners. The researcher’s most striking finding is that late L1 learners perform significantly worse in morphology, syntax and phonology than late L2 learners. This contrast
appears to be unrelated to non-linguistic cognitive or motivational factors but is attributed instead to very late L1 learners having developed an incomplete brain/language system during childhood brain maturation.
According to the researchers, L2 learners, conversely, have already established a fully developed brain/language system during this period. Based on their findings, Mayberry and Kluender conclude from the more substantial age-of-acquisition effect in adult L1 than in adult L2 learners that there is a critical period for the acquisition of a first language only, whereas L2 development is affected by other factors.
Several scholars have criticized this hypothesis and indicate specific limitations to the proposed account and of the data presented in its defense. Birdsong and Quinto-Pozos (2018) claim that Mayberry and Kluender’s comparison of late L1 versus L2 signers fails to provide a role for bilingualism, indicating that comparing bilinguals with monolinguals will always reveal divergences, regardless of the age of L2 acquisition. Furthermore, Emmorey (2018) doubts the claim that if L2 outcomes were fully under the power of a critical period, they would not be as variable as they are and thus affected by cognitive or motivational factors. Moreover, he claims that this variability does indeed extend to L1 learners. Lillo-Martin (2018) indicate that there may be domain-specific differences in critical periods, with different age cutoffs for different linguistic phenomena, a hypothesis that is not considered in Mayberry and Kluender’s study.
Mayberry and Kluender (2018b) have provided a rebuttal and stress areas in which they agree with the critiques put forth. The researchers furthermore attempt to explain their motivations, admit current limitations of their proposal, and welcome suggestions for future research. What emerges most importantly from Mayberry and Kluender’s (2018b) response is the modification of their original claim of a critical period for L1 acquisition only. The researchers now entertain the idea that there are critical periods for both L1 and L2 acquisition, but with less severe effects on late L2
acquisition than on delayed L1 acquisition, due to L2 speakers having acquired another language early in life.
Part II. A Constructionist Approach to Language
Acquisition
2.1 A theoretical framework for first language acquisition
As the previous chapter has shown, neuroplasticity is proven to aid in the acquisition of both L1 and L2, and there is growing evidence for the existence of critical periods for language learning due to delayed prefrontal cortex development in children. Turning now to the theoretical framework surrounding child language acquisition, a great debate resurfaces: do humans possess a biological endowment for language? Once synapses in the brain are formed, they may be undoubtably strengthened through stimulation, or eliminated through the process of pruning, thus the unparalleled power of the brain to reinforce and reorganize its neural networks in response to stimulus is undisputed. However, how can the earliest manifestations of the body’s most miraculous cognitive function be accounted for? Do humans possess a biological predisposition which enables the processing and production of language? Are children born expecting to encounter nouns and verbs? More importantly, is the input given to children, together with processing and cognitive constraints, enough to allow them to actually learn their native languages?
Since the advent of Chomsky’s Language Acquisition Device (LAD) in the 1960s, a theory which argued that fundamental aspects of syntax were simply too complex to be learned and were thus innate, there has been much discussion in the field regarding the existence of a biological endowment for language, i.e. Chomsky’s Universal Grammar (UG). Though the Chompskian hypothesis continues to serve as linguistic doctrine for many, it must be noted that research
concerning the input given to children in infancy and early childhood was scarce during the
development of the LAD, as it was in the initial decades of Universal Grammar. In the 1960s it was likely difficult to imagine that exceedingly complex structures such as language might indeed be learned; less burdensome was the practice of equating the human brain to the super computers of the day and arguing that language was nothing more than a complex, algebraic system, immune to any communicative or cognitive constraints.
Nevertheless, as a component of the nativist theory, the concept of a language acquisition device remains intriguing. LAD asserts that humans are born with the instinct or "innate faculty" for acquiring language, and given the complex nature of grammar, such an argument appears quite persuasive. Young children learn to speak with relative ease, are given no formal instruction in their native languages, and produce errors which an adult L2 learner would likely never make. It is miraculous indeed to witness a two-year-old child begin to string words together, and even more astonishing to hear that young child repeat a long and complicated “big word”; one that perhaps he or she has heard from a well spoken parent. Language is hugely complex, and yet very young children begin to acquire and subsequently master it rather effortlessly and fairly quickly.
Admittedly, the manner in which this occurs has historically been quite mysterious, and as a result, the premise for an innate language learning ability is far from risible.
Poverty of the Stimulus
Chomsky’s argument for the Poverty of the Stimulus (POS) is compelling. POS asserts that unless children possessed significant innate knowledge of grammar, they would not be capable of
acquiring their native languages. A principle aim of modern Generative Grammar has been to discover invariant properties of human languages that reflect, as Chomsky states "the innate schematism of mind that is applied to the data of experience" and that "might reasonably be
attributed to the organism itself as its contribution to the task of the acquisition of
knowledge.” (Chomsky, 1971, p. 48). Proponents of the LAD argue that such invariances include the structure dependence of grammatical rules, and in particular, certain constraints on question formation (Raymond, 2003).
Hence, several patterns in language are claimed to be unlearnable based on positive evidence alone; one example of these is the hierarchical nature of languages. The grammars of human languages produce hierarchical structures, and if it is true that human languages are capable of infinite recursion, or as Chomsky describes it, “the potentially infinite embedding of one linguistic
representation within another of the same type for any given set of sentences generated.” (Chomsky et al., 2005, p. 59), it follows that any given set of sentences generated by a hierarchical grammar capable of infinite recursion produces an indefinite number of grammars which may have yielded the same data. This would make learning any such language unachievable based on positive evidence alone.
An additional example of a linguistic pattern claimed to be unlearnable through positive evidence alone is that of subject-auxiliary inversion in interrogative constructions, e.g. You are sad, Are you sad? Theoretically, a child may form two hypotheses regarding this construction: 1. In order to form the interrogative, the first auxiliary verb encountered in the construction must be moved to the beginning of the sentence, or 2. The “main” auxiliary in the construction must be moved to the beginning of the sentence. In a construction containing only one auxiliary verb, as in the
aforementioned example, both suppositions formulated by the child produce the same result and there is thus no room for error.
But what of sentences which include more than one auxiliary verb? Though critics may argue that a child would never be presented with such a complex construction, a possible example might be the following: Anyone who is hungry can have a snack after recess. Should a child employ the “rule” which he or she applies to a single auxiliary sentence or rather, “front any auxiliary verb in order to form the interrogative”, the following results would be achieved: 1. Is anyone who hungry can have a snack after recess?; 2. Can anyone who is hungry have a snack after recess? Thus the application of these “rules" yields two different results: one that is clearly ungrammatical, and one that is acceptable for the English language. It follows that a child would have a 50% chance of creating a grammatically acceptable interrogative construction every time, with a remaining 50% chance of uttering total nonsense.
Hence within the framework of Generative Grammar it may be assumed that the second “rule”, or that of fronting the main auxiliary verb of an affirmative sentence in order to form the interrogative, is innate and represents some of the implicit linguistic knowledge that all human beings possess
(Lasnik & Uriagereka, 2002). It follows that if this were not the case, one might expect the
sentence, Is anyone who hungry can have a snack after recess to be uttered by children until formal, grammatical instruction in the English language takes place, and for most children, that would mean well into primary or elementary school.
Thus the POS argument asserts that there are patterns in all natural languages which are cannot be learned by children through exposure to positive evidence alone; positive evidence includes those purely grammatical constructions that a child accesses by observing the speech of others; it tells a child what constructions are acceptable. Negative evidence, conversely, is linguistic input which is ungrammatical, i.e. when a parent or caregiver corrects a child’s speech; it tells a child what constructions are unacceptable in their native language. According to the POS argument, it is postulated that children receive only positive evidence for key linguistic patterns, and it is of course evident that children do not receive formal instruction in the grammar of their native language until much later on in life.
A summary explaining LAD by Chomsky himself states that languages are infinite pertaining to the sequence of word forms (strings) and grammar which comprise them. These forms organize
grammatically correct sequences of words that can be pooled over a limited lexicon of each independent language (Chomsky, 1965). Consequently, LAD is tasked with selecting from an infinite number of grammars the one which is correct for the language that is presented to the young child. However, what if the child assumes an active role in this process? Are there questions to which the LAD, and more specifically the POS have not provided an answer?
Though an undoubtedly sound argument, POS has been widely critiqued. A recently advanced theory is that positive evidence is actually enough to learn the various patterns which linguists claim to be unlearnable, through the sole employment of the later. It has been posited that mechanisms in the brain which recognize statistical patterns may account for first language acquisition.
Researchers using neural networks have programmed computers to learn rules such as the “fronting of main auxiliary verbs” in order to form interrogative constructions, and have successfully
extracted hierarchical structures, all through the use of positive evidence alone (Solan et al., 2005).
Furthermore, criticism has arisen regarding the assumption that children rarely encounter negative evidence. Within the greater context of statistical learning, Pullman (1996) asserts that children are likely presented with negative evidence in the following way: if a certain linguistic pattern is never encountered by the child, then he or she may consider the absence, and frequency of absence of such a pattern, as sufficient negative evidence from which he or she is able to determine what constitutes an unacceptable construction in his or her native language (Pullman, 1996). Thus it may be hypothesized that that which children do not encounter on a regular basis not only does not go unnoticed, but it is statistically accounted for.
Additionally, doubts have arisen as to whether or not human languages are truly capable of infinite recursion. No studies have been carried out which involve an infinitely long sentence, as such a task would be impossible. On the contrary, studies have show that people tend to find four of more layers or recursion as convoluting the original message (Luuk & Luuk, 2011). Chomsky has long argued that these cases are best explained by restrictions on working memory, and though this provides a reasonable explanation, empirical evidence is lacking. However, even amongst those who are skeptical about mentally represented, recursive-grammatical-knowledge, it has generally
been assumed that limits on embedding have something to do with human limits on language processing.
Tab.1 Suppositions of and opposition to the Poverty of the Stimulus argument
Despite arguments against the LAD, it is still controversial to posit that children actually learn their native language. Notwithstanding the contention in the field however, there is a growing body of evidence for the learning potential of young children which points to a child’s socials skills, vast cognitive ability and tendency to imitate. Concerning the assumption of the POS, vast corpora have been collected which report in detail the linguistic input given to children and data has shown that though it is simplistic and repetitive in nature, it is immense.
In 1984, Brian MacWhinney, a professor of Psychology and Modern Languages at Carnegie Mellon University, created CHILDES (Child Language Data Exchange System), a central repository system for data on first language acquisition. The principle use of the CHILDES database is analyzing
Supposition What the POS does not explain
Children are only exposed to positive evidence during first language acquisition
Could lack of negative evidence itself inform a child as to what constructions are unacceptable in his or her native language?
Positive evidence alone is not sufficient input for language acquisition
Are there mechanisms in the brain which recognize statistical patterns in speech, in the face of little input?
Children are born able to extract the rules and principles from their native language
Exactly what information is innate, and how is this innate information represented in the brain? Languages are capable of infinite recursion How may infinite recursion be studied and proven
young children’s language directed to adults, i.e. linguistic interactions between mothers and their children and other caregivers. Though its earliest entries date from the 1960s, it currently houses transcripts, audio and video in 26 languages from 130 different corpora, all of which are publicly available worldwide (MacWhinney, 2000).
As numerous corpora of child language are currently available to researchers, linguistic input to children has begun to be investigated more thoroughly and the proposal that children actually learn their native language is gaining momentum. Before analyzing the nature of linguistic input given to children, a legitimate inquiry may be made: even with sufficient input, are young children capable of such complex learning? Young humans are generally viewed as poor learners, suggesting that innate factors are primarily responsible for the acquisition of language. Surprisingly, a recent study has show that even honey bees, which constitute a traditional model for studying learning and which are insects endowed with much smaller and much more underdeveloped brains than humans, are indeed accomplished learners (Giurfa et al., 2001).
Complex learning in honeybees
In his study Giurfa (2001) demonstrated that honeybees are able to distinguish between concepts of ‘sameness’ and ‘difference’ through being trained to find food within a Y-shaped maze. In the study bees entered the maze individually through the bottom of the Y, where they were met with a
stimulus. The maze gave way to a fork where the insects were then forced to choose a path. At the entrance to one of the paths was a stimulus that directly matched the stimulus the bees had
previously encountered. At the entrance to the opposing path, a different stimulus was placed. If the insects chose the path where the matching stimulus was found, they were rewarded with food placed just beyond it. If they chose the path containing the differing stimulus, no food was offered
as a reward. In surprising results, the bees were found to learn to match the simuli at a rate which exceeded chance in four out of seven trials.
In somewhat surprising fashion, after learning to match the training stimuli, the bees were tested with entirely new stimuli and were able to successfully transfer their knowledge to the new stimuli with an average of 75 percent accuracy. These findings demonstrate that honeybees are not only capable of learning the concepts of ‘sameness’ and ‘difference’, but are also able to extend acquired knowledge to entirely different forms of stimuli (Giurfa et al., 2001).
Thus if honeybees, with brain volumes of approximately 1 mm3, can learn such abstract concepts as the distinguishing of what is different from what is the same, why must we categorically accept that critical aspects of syntax are unlearnable by children? Arguably, children are highly motivated learners and surely a child’s urgency to communicate his or her needs rivals that of a honeybees desire to find a source of food. If these factors are combined, together with a child’s vast memory for language, it becomes less and less controversial to posit that native languages may be, at least partially, learned. The search for a theoretical framework which posits that languages are actively acquired, and that they are constructed by speakers on the basis of input together with general cognitive, pragmatic, and processing constraints comes to a natural conclusion within the theory of Construction Grammar.
Language is constructed
Beginning in the 1980s, Construction Grammar emerged as a theory of language which posited that that the meaning of idioms and fixed expressions was not simply a function of the meanings of their parts. World renowned linguistics and forerunners in Constructionist approaches Charles Fillmore, Paul Kay and George Lakoff authored pioneering works such as Lakoff’s “There-Constructions,”
published in his volume Women, Fire and Dangerous Things. Lakoff argued that the deictic “There-Constructions” were based on the pragmatic meaning of the construction itself, and that variations on the later could be seen as simple extensions, using form-meaning pairs of the central
construction. (Lakoff, 1990). Equally groundbreaking was the work of Fillmore et al. (1988) on the English “Let alone” construction. Innovative was its in-depth explanation and accounting for the syntax and pragmatics of the English “Let alone” construction, and its demonstration that
constructions constitute their own, unique semantic units (Fillmore et al., 1988).
Since the 1990s, the theoretical framework of Construction Grammar has witnessed a shift towards a usage-based model and several corpus-based methods of analysis have been developed. Much investigation into first language acquisition has been done and recent Constructionist approaches have attempted to provide evidence that languages, and their constructions, are indeed themselves, constructed.
Linguistic constructions per se have been studied and analyzed for centuries, but it is only until recently that a theoretical approach has allowed specific patterns and wider generalizations to be directly observed and wholly accounted for. Interestingly, the term “construction” has a twofold meaning. In her seminal volume Constructions at Work, Adele Goldberg notes that “The primary motivation for the term is that constructionist approaches emphasize the role of grammatical constructions: conventionalized pairings of form and function. In addition, constructionist
approaches generally emphasize that languages are learned—that they are constructed on the basis of the input together with general cognitive, pragmatic, and processing constraints.” (Goldberg 2006, p. 4).
A construction is defined as a paring of form and function, or rather a form, and some sort of meaning. Constructions include items such as idioms and words, but also more traditional
constructions such as the passive or the caused motion. These units are in essence, form-meaning pairings associated with autonomous, non-compositional abstract meanings, independently from the lexical items occurring within them. Constructions range from morphemes (e.g., pre-, -ing), to filled or partially-filled words (e.g., beachball) to idioms (e.g., Orange is the new black) to more abstract patterns like the Ditransitive [Subj V Obj1 Obj2] (e.g., She bought her a book) (Goldberg, 2006).
Tab.2 Examples of possible constructions in English
Argument structure: a radical departure from other theories of grammar
Differently from mainstream generative grammar, constructionist approaches highlight the detailed semantics and distribution of particular words, grammatical morphemes, and cross-linguistically unusual phrasal patterns; the premise behind this method of analysis is that the profound semantic, pragmatic and complex formal constraints on these patterns readily extend to more general, simple,
Morpheme e.g. pre-, -ing
Word e.g. apple, and
Complex word e.g. aardvark, shoo-in
Partially filled complex word e.g. [N-s] (for regular plurals)
Filled idiom e.g. orange is the new black
Partially filled idiom e.g. push <someone> to the brink, send <someone> packing
Covariantional conditional The Xer the Yer (e.g. the bigger they are, the harder they fall
Ditransitive Subj V Obj1 Obj2 (e.g. he gave her a book; she made him dinner)
Passive Subj aux VPpp (PPby) (e.g. this house was built by my grandfather)
Comparative e.g. Sara is taller than you
or regular patterns. Furthermore, it is thought that constructions are subject to methodical variation depending on the verb classes with which they interface (Goldberg, 2006).
All linguistic patterns constitute constructions, so long as some aspect of their form or function is not calculable from their component parts or from other known existing constructions. Though constructions are present at any level of linguistic analysis, it is the concept of argument structure which represents a radical departure from other theories of grammar.
Divergent surface forms are typically associated with slightly different semantic and or discourse functions. Constructions such as English’s ditransitive are posited to be associated with an abstract semantic content which is not found within its paraphrase counterparts. The ditransitive
construction involves a predicate with three arguments; these three arguments are identified as ‘‘agent,’’ ‘‘recipient,’’ and ‘’theme’’. The roles of the arguments are determined by the meaning of the construction, e.g. Sara bought Anna a book., or, Subj V Obj1 Obj2, where the main predicate is thought of as evoking the notion of ‘’causing someone to receive something’’ or ‘’give,’’. In other words, Sara bought Anna a book because she intended to present her with something through the act of giving.
Goldberg (2006) states, “As is the case with other constructions, including words and morphemes, constructions typically allow for a range of closely related interpretations. The
‘‘CAUSE-RECEIVE’’ predicate associated with the ditransitive construction is subject to systematic variation depending on which verb class it interacts with.” Goldberg, 2006, p. 20) Hence, the equivalent yet semantically differing paraphrase of the following construction, Sara bought the book for Anna, may be analyzed for a divergent semantic content, i.e., Sara bought the book for Anna because Anna did not have time. Thus it must be noted that Constructionist suppositions do not derive one
construction from another, as is generally done in mainstream generative theory (Goldberg, 2006, p. 10).
Furthermore, Goldberg’s argument against derivational theories and the importance that is often attributed to the semantic similarities between the ditransitive construction and its paraphrase counterpart is soundly defended in her Surface Generalizations Hypothesis. Goldberg (2006) affirms: “…there are typically broader syntactic and semantic generalizations associated with a surface argument structure form than exist between the same surface form and a distinct form that it is hypothesized to be syntactically or semantically derived from”. If follows that there is an inherent danger with overemphasizing the semantic similarities between the ditransitive and its paraphrase, as, according to Constructionist approaches, they constitute unique, semantic units (Goldberg, 2006).
Another supporting argument in favor of constructions as independent and primitive objects of grammar is the flexibility with which argument constructions and verbs interact. The surface meaning of the intransitive verb to laugh, as seen in the sentence, Martha laughed., may be
overridden by the caused motion construction, as in the sentence, Martha laughed the actor off the stage. In the latter example, the typically intransitive meaning of laughing is construed to mean “making something move by the act of laughing”.
Thus if we view language as containing innumerable constructions, we may consider our speech to be made up of nothing more than countless, idiomatic expressions. What implications does this perspective have on first or second language acquisition, if any? If constructions make up the bulk
of our everyday utterances, may we assume that each one of us contributes to the constructing of language? What are the cognitive, social and communicative mechanisms involved in this process?
2.2 Language is learned: Statistical learning and word segmentation
In the past twenty years much has been discovered concerning a child’s ability to track statistical regularities in naturally occurring speech and more importantly, recognize patterns within linguistic input. These insights, combined with what is now known regarding the nature and breadth of the input given to children, have given weight to the presupposition that native languages may indeed be learned. Astonishingly, long before producing their first intelligible utterances, infants are capable of word segmentation and begin to recognize and keep account of lexical items.
In what is known as experience-dependent learning, children develop the ability to identify words in naturally occurring speech through the keeping track of reoccurring paradigms, just as one would collect statistical and probabilistic information from a set of data. This remarkable process is referred to as statistical learning, and in its broadest sense, entails the discovery of patterns in the input. This type of acquisition ranges from supervised learning found in operant conditioning, e.g. learning that a certain behavior leads to reinforcement or punishment, to unsupervised pattern detection, to the sophisticated probability learning exemplified in Bayesian models. The types of patterns tracked by a statistical learning mechanism may be simplistic in nature, such as frequency count, or more complex, such as conditional probability. Similarly, the concepts based on which computations are carried out, may vary in complexity from geometric shapes and faces to linguistic elements such as syllables and syntactic categories (Romberg & Saffran, 2010).
Returning now to arguments put forth in the previous chapters concerning neuroplasticity, an experience dependent process may be defined as the following: within the brain, modifications in neurochemistry, anatomy, electrophysiology, and neuronal structure following various individual
