The identification of American English vowels by native speakers of Japanese before three nasal consonants

Abstract

Native speakers of Japanese identified American English vowels that are uttered before three nasal consonants /m, n, ŋ/ and three oral stop consonants /b, d, ɡ/. Of the seven vowels /i, ɪ, eɪ, ɛ, æ, ɑ, ʌ/, /æ/ was generally less accurately identified before nasal consonants than before oral stop consonants, and this tendency was stronger when /ŋ/ follows. This tendency is probably attributed to the extended raising of /æ/ before /ŋ/ and the Japanese listeners’ limited sensitivity to differentiate three nasal phonemes in coda position. /ɪ/, on the other hand, was identified more correctly before /ŋ/ than before the other two nasal consonants, also probably because the vowel is raised before /ŋ/. This vowel was more often misidentified as /ɛ/ before /m/ and /n/. /ɑ/ and /ʌ/ were less accurately identified before stop consonants, but after nasal consonants, /ʌ/ was more often misidentified as /ɑ/. /ɑ/ and /ʌ/ may sound alike to Japanese listeners in every context, but before nasal contexts, both of these vowels may sound closer to the Japanese vowel /o/. The results generally revealed that identification accuracy cannot be solely accounted for in terms of the place of articulation of the following consonant.