An Acoustic Comparison of Vowel Length Contrasts in Standard Arabic, Japanese and Thai

In our earlier perception study, we observed that familiarity with first language (L1) phonemic length contrasts in Japanese does not transfer optimally into an unknown language, Arabic. We hypothesized that this finding is related to cross-language differences in how vowel length contrasts are phonetically realized. The present study compares vowel length contrasts that are phonemic in three typologically unrelated languages, i.e., standard Arabic, Japanese and Thai, in an attempt to understand the extent to which vowel length contrasts are similar or dissimilar in these languages. Acoustic measurements showed short and long categories were clearly differentiated in all three languages and the short-to-long ratio did not substantially differ across languages. This suggests that listeners attend to more than just acoustic vowel duration in making perceptual judgments on short vs. long vowels.