ACOUSTIC ANALYSIS OF THE PRODUCTION OF UNSTRESSED ENGLISH VOWELS BY EARLY AND LATE KOREAN AND JAPANESE BILINGUALS 論文 Borim Lee・Susan G. Guion・Tetsuo Harada ·2006-08-09 ·『Studies in Second Language Acquisition』 28(3) pp. 487-513 doi:10.1017/s0272263106060207