Acoustic and articulatory dynamics in second language speech production : Japanese speakers' production of English liquids

Nagamine, Takayuki and Kirkham, Sam and Nance, Claire (2024) Acoustic and articulatory dynamics in second language speech production : Japanese speakers' production of English liquids. PhD thesis, Lancaster University.

Text (2024NagaminePhD_2)
2024NagaminePhD_2.pdf - Published Version
Download (33MB)

Abstract

This PhD thesis considers how second language (L2) learners use dynamic, timevarying phonetic cues to produce consonants in L2 speech, with the case of firstlanguage (L1) Japanese speakers’ production of L2 English liquids as a testing ground. Previous research has shown that L1 Japanese speakers have substantial difficulty in producing L2 English liquids because of the L1 influence. The articulatory mechanism that causes the difficulty, however, remains unclear due to the lack of articulatory data and consideration of dynamic properties, which could be predicted to be an area of difficulty given existing articulatory descriptions of Japanese and English liquids. Acoustic and articulatory data were collected from a total of 55 participants, including 41 L1 Japanese speakers and 14 L1 North American English speakers. Midsagittal tongue movement was recorded using ultrasound tongue imaging while speakers read aloud Japanese and English liquid consonants appearing word-initially, word-medially and word-finally. The data were analysed both acoustically and articulatorily, resulting in five empirical studies included in the thesis. Acoustic and articulatory analyses of wordinitial liquid-vowel sequences in L1 and L2 English suggest a greater variability in tongue dorsum height across different vowel contexts than L1 English speakers, which is not readily observable in static analysis. Studies investigating L1 Japanese speakers’ production of L2 English allophony commonly show a mismatch between acoustics and articulation, suggesting that L1 Japanese speakers may utilise different sets of articulatory strategies to achieve target-like acoustic output. Taken all these findings together, this PhD thesis proposes that dynamics involved in speech production could be a source of L2 speech production difficulty. It demonstrates that the combination of the dynamic and articulatory aspects involved in L2 speech production could further advance our understanding of the specific obstacles L2 learners encounter in the course of L2 speech learning.