1 CHAPTER 6. CONCLUSIONS
The ISLE corpus has turned out to be a very useful spoken language resource for the pronunciation analysis I carried out in this thesis. The language material that the ISLE corpus provides is highly versatile. Even if this material was not collected for the particular type of research I conducted, it proved to be extremely useful for the analysis of pronunciation errors that Italian and German English language learners make.
Speech recordings were collected from adult, non-native, (mainly) intermediate English language learners. These second language learners were 23 German speakers and 23 Italian speakers. The corpus contains 1.92 gigabytes of WAV files and 17 hours, 54 minutes, and 44 seconds of speech data. The corpus has been annotated at the word and phone level, to highlight pronunciation errors such as phone realisation problems.
Statistics extracted from the ISLE corpus enabled me to realise which are the most common sources of English pronunciation errors for German and Italian native speakers. For both German and Italian native speakers the corpus provides empirical evidence of which are the most difficult phones and which phones account for most errors. The Italian speakers made an average of 0.54 phone errors per word with a standard deviation of 0.75, while the German speakers made an average of 0.16 phone errors per word with a standard deviation of 0.42. Statistics providing the frequency with which a particular phone was affected by pronunciation errors has proved to be extremely useful to conduct quantitative analysis.
Examples of the pronunciation errors have been evidenced, transcribed, and analysed. For both the German and Italian native speakers, analysis of pronunciation errors showed that most of the errors are attributable to L1 interference. In other words, the analysis of pronunciation errors in German and Italian English language learners confirms the initial assumption that difficult
2 phones in the target language are mainly substituted with most similar phones of the native language of the speaker. Another interesting outcome was the considerable contribution of short function words to the overall share of pronunciation errors. I believe this type of error to be due to the fact that language learners are more concentrated when pronouncing more complex words. Short function words could be considered as easier by language learners and therefore they put their focus less on these words. This could paradoxically lead to more errors because too little worrying of doing well may get in the way of success. Furthermore, for the Italian speakers schwa insertion accounts for almost 7% of the errors they make. Most of Italian words end with vowels. Schwa insertion is attributable to L1 interference, as most of the pronunciation errors.
However, I believe that some problems concerning the choice of the speakers arise when analysing the two second language learning groups in comparison to the English language. The first obvious problem is the fact that the creators of the corpus aimed to balance the speaker set for age, gender, and proficiency. Given the relatively small number of volunteer speakers, it was not possible to maintain this intention. In fact, the speaker set ended up with more male (32) than female (14) volunteers. It would thus not be logical to try to draw conclusions about gender-based language variation.
Furthermore, the ISLE corpus shows a clear difference in proficiency between the two language groups. I believe this difference to be only partly due to the greater phonological similarities between German and English than between Italian and English. The German speakers clearly demonstrate higher general proficiency levels than the Italian speakers. For the selection of the speakers, it could thus be useful to base proficiency ratings not only on a self-judgement of speakers, but also on proficiency tests. This could help to create a more balanced learner corpus.
It could also be advantageous to have more information about the speakers and about recording settings in order to make probable speculations about
3 pronunciation errors due to individual factors. Having knowledge of the speakers’ exact age could be useful to researchers focusing on age-related language studies or dealing with theories concerning generative grammar. Being aware of the speakers’ socio-cultural background could also be helpful, especially when focusing on individual factors (i.e., motivation) appearing in second language learning. It would also have been possible to make some more specific hypotheses about interlanguage phonology if we would have known if the speakers also study other second languages. Having more information about the recording settings could help to decide whether emotional constraints were influencing the pronunciation errors. Some pronunciation errors could be possibly due to anxiety factors. Being uncomfortable or too comfortable in the speech recording setting could compromise speech production.
It could also be interesting to supplement the corpus with more speakers. This could be done with more Italian and German native speakers or with speakers of other languages with German and neo-Latinate roots such as Dutch, Norwegian, French, or Spanish. (or maybe even with speakers of extra-European languages.) In any case, I would continue to use the same reading exercises which I believe were chosen very well by the creators of the ISLE corpus. The exercises introduce the complete number of phones possible in English. From a point of view of problem phones in English as a second language, the reading exercises seem to me thus pretty satisfying.
The type of reading exercises used in the ISLE corpus could also be expanded to include possible diachronic approaches. The reading exercises could be recorded not only by adult English learners, but also by English learners of different ages. The exercises could be recorded in several different learning moments as well in order to make diachronic studies possible.
However, I am aware of the fact that such proposals are highly ambitious or maybe even utopian. Collecting, annotating, and analysing a learner corpus is highly time and effort consuming. Most suggestions for further research
4 probably will remain just mere ideas. In any case, the amount of potential further research that several different types of approaches utilizing spoken corpora such as the ISLE corpus seems to be endless.
From a linguistic point of view, another issue worthy to mention is the phone set used for phone annotations in the ISLE corpus. The chosen phone set to fulfil this task, was the Entropic’s UK English phone set. It is highly understandable that it was simpler to adopt this phone set for displaying and printing reasons. However, from a linguistic perspective I believe that it is more useful to deal with the IPA phone set. I adopted thus the IPA phone set to transcribe the pronunciation errors found in the ISLE corpus, as IPA is more appropriate for the type of linguistic analysis that I conducted in this thesis. Hoping for (and believing in) future re-use of the ISLE corpus by other researchers, it should be feasible to improve automatic transcription software adopting IPA labelling.
In any case, what definitely should be done first is to spend considerable efforts on creating a more balanced corpus, in terms of both gender balance and proficiency level. This is important to be able to furnish a completely correct, reliable, and, generalisable analysis.
Criticisms aside, the ISLE corpus was to me an extremely useful and interesting resource for linguistic analysis. The analysis of pronunciation errors in the ISLE corpus could also be particularly useful for the improvement of second language teaching. It is of vital importance that both the teacher and the learner become aware of pronunciation errors belonging to a particular language group. It is also important to be aware of individual differences in pronunciation. The ISLE corpus can provide such information. Teachers need to be aware of the features of learner language produced by their students. If teachers know exactly which are the problem phones, it is possible to focus on these and to improve pronunciation. Furthermore, making the second language learners aware of what they do wrong is a useful way to help them to get over these errors. The ISLE corpus could be used in the classroom by putting language learners in
5 contact with the audio data of mispronunciations. I believe that listening to authentic erroneous speech data is the most interesting (and probably also the most powerful) way to make language learners aware of their pronunciation errors and of those that their native language group is likely to make.
In conclusion, the ISLE corpus was to me a totally new way to approach linguistic reality. The ISLE corpus has turned out to be an extraordinary resource of linguistic analysis with a high potential of further re-use. I have confidence in the fact that the ISLE corpus will continue to be a generic language resource for the wider research community.
