Interlanguage Phonology and Accentedness: An Experimental Study of Thai Final Nasal Consonants in Chinese Students Learning Thai

This paper provides an experimental study of interlanguage phonological characteristics of Chinese students learning Thai as a foreign language and the accentedness perceived by native Thai speakers. Both production and perception experiments were designed to see how Chinese students acoustically produced Thai final nasal consonants and how Thai native speakers perceived these Chinese-accented nasals. The production experiment compared the acoustic features of Thai final nasal consonants (i.e. /m/, /n/, and /ŋ/) produced by Chinese students and native Thai speakers (n = 5 in each group), who provided speech samples from a wordlist reading task, consisting of 28 words (840 tokens). Nasal acoustic properties of 840 tokens (duration, nasal murmurs, and formant transitions) were examined. The findings showed that the Chinese students produced significantly longer nasal duration and more drastic formant transitions compared to the native speakers. The perception experiment analyzed how native Thai raters (n = 10) rated speech samples concerning degrees of accentedness by using a 5-point Likert scale with 5 as the most native level. Based on this, the native Thai raters rated the Chinese students’ speech as 3.22 on average, while native Thai speech was judged with an average score of 4.65, which demonstrated that native Thai raters could distinguish foreign speech from those pronounced by native speakers. To find out to what extent nasal acoustic characteristics in Chinese students’ interlanguage phonology contributed to the degree of accentedness, stepwise regression analyses were utilized to discover that nasal duration was particularly important in accurately predicting accentedness in Thai with Chinese accents.