Cross-language study of perception of the oral-nasal distinction.

To investigate the effect of linguistic experience on the perception of the oral-nasal distinction in vowels, Hindi and American English speakers were tested on identification and discrimination of four speechlike series generated by articulatory synthesis. In experiment I, no language-group differences were found in the discrimination of either a consonant series, [ba-ma] (a phonemic contrast in both languages), or a vowel series, [ba-bã] (phonemic only for the Hindi speakers). The vowel results were due to floor effects which obscured differences across language groups. Experiment II examined perception of two modified vowel series, one which increased the interval between members of discrimination pairs and one that extended the range of velar port opening. Cross-language differences in discrimination were found. Hindi perception of the oral-nasal distinction was categorical. English speakers' perception of the vowel series was more continuous. They accurately discriminated differences not only across categories, but also within the oral category. These findings indicate that linguistic experience can influence listeners' perception of vowels, but the effect is different from that shown for consonants.