This research investigates the difficulties that Spanish, Russian, and Japanese speaking adult learners of English have in hearing and pronouncing differences among vowel sounds. English includes 11-12 distinct vowels sounds, whereas the three languages listed above have only 5-6 vowel sounds. Thus, for instance, where Spanish, Russian and Japanese have one vowel (similar to the [a] sound as in "hot"), English has three different vowels (the sounds in "hat", "hot" and "hut") that are very similar to each other and to the single vowel sound in Spanish, Russian and Japanese. Other confusing vowels include those that distinguish word pairs such as "luck-look", "mate-met", "feet-fit" and "pit-pet". To the English learner, these word pairs may sound like the same word (i.e. homonyms). A failure to pronounce these vowel sounds correctly leads to 'foreign-accented' speech that may interfere with communication. What is less obvious is that failures to perceive the differences between vowels may interfere with English language learners' ability to understand English speakers' utterances. As adult learners of English gain experience in listening to and speaking the new language, some of these perception and production problems are ameliorated; however, even after years of immersion in an English speaking environment, some vowel sounds continue to be confused, especially in difficult listening conditions (in noisy rooms, when the language learner is otherwise occupied, or is fatigued).
This research project examines the perceptual difficulties of Spanish, Russian and Japanese adult English learners using speech materials and listening conditions that more closely simulate 'real life' listening conditions. Both behavioral measures and brain measures of perceptual processing will be obtained on groups of listeners who vary across a wide range of English language experience. From the results, the underlying processing difficulties of these English learners and the effects of non-optimal listening conditions on their perception and production performance can be determined. These findings will contribute to basic theories of speech processing and will also lay an empirical foundation for improving English-language testing and instruction for immigrant populations. In an increasingly globalized economic and political world, understanding and ameliorating communication problems by speakers of different 'mother tongues' is of great importance. Spoken English proficiency is extremely important for the educational and economic advancement of immigrant populations in the USA.
