The Effect of L1 Vowel Inventory Size on The Perception of New Rounding-Contrasted Vowels

Abstract

This study is set out to address the impact of L1’s vowel inventory size on the accuracy of discrimination between novel vowel contrasts. While there are several studies investigating this predictive factor, they reached contradictive conclusions, which was mainly due to the typological similarity between the languages studied. In order to address this question while avoiding the issue of typological relation, two groups of participants were gathered from two unrelated native languages differing widely in terms of the size of their vowel inventory. The languages are Arabic, with only three to five duration-contrasted sets of vowels, and English, with up to 13 monophthongs, depending on the dialect. Using an AX forced choice discrimination task, both groups were tested on their ability to discriminate between two high back vowels from Thai, which are the ones in the /ɯ/-/u/ contrast. The results showed that both groups performed very well in discriminating between the two vowels, highlighting the importance of rounding as a distinctive feature in vowels in addition to formant frequencies. More importantly, the results also revealed that the English group (with a larger vowel inventory size) significantly outperformed the Arabic group (with a limited vowel inventory size). This suggests that a gradual approach to L2 teaching based on the vowel inventory size could be beneficial.