Adult L2 Japanese learners’ production and perception of Vietnamese monophthong vowels

This paper reports a study that investigated the role of prior native or first language (L1) phonological and phonetic learning on the integration of vowel quality features in the acquisition of second language (L2) vowels by examining adult L2 Japanese learners’ perception and production of Vietnamese monophthong vowels in an identification, an imitation and a read aloud tasks. Two groups of participants took part in the study (11 control Vietnamese, 10 Japanese learners of Vietnamese). The stimuli consisted of 9 Vietnamese monophthongs /i, e, ɛ, a, ɔ, o, u, ɤ, ɯ/ and 5 simple Japanese vowels /i, e, a, o, ɯ/. The results showed that Japanese learners of Vietnamese failed to distinguish the Vietnamese vowel pairs /ɛ/-/e/, /o/-/ɔ/ and /u/-/ɯ/ accurately in their perception. In terms of production, Vietnamese vowels /ɛ/ and /e/ merged in vowel space. Moreover, the three Vietnamese vowels /ɔ/, /o/ and/ɤ/ produced by Japanese learners in both production tasks tend to cluster together. Vietnamese vowels /u/ and /ɯ/ produced by Japanese learners also overlapped in vowel space. In general, the findings of this study showed that Japanese learners transfer their L1 vowel quality features into the production of Vietnamese vowels.