Perception of Japanese accented English segments in words

Abstract We studied the perception of segmental boundaries in native English and Japanese accents in terms of foreign accentedness, intelligibility and discrimination accuracy. Five American English vowels /ɪ, æ, ɑ, ə, ɝ/ and seven consonants /r, l, v, θ, f, t, k/ were extracted from English and Japanese words produced by an American English-Japanese bilingual speaker, and manipulated, with the acoustic properties shifting gradually from 100% Japanese to 100% American English using segmental foreign accent and gradation techniques. Perception tests were conducted online with native American English speakers, and groups of Japanese speakers with either low or high English proficiency. All three groups showed a negative correlation between the degree of foreign accent and intelligibility. Also, there was a greater reduction in intelligibility due to acoustic deviation from the native norm in consonants than in vowels. The results suggest that more standard-like accent does not necessarily improve intelligibility, thus highlighting the importance of FA research in terms of segmental accuracy.