An Acoustic Analysis of Korean Speakers' Production of English Vowels 
Hee Youn Cho, Yoonsook Mo, and Sook-Youn Yoon 
University of Illinois at Urbana-Champaign 

This paper presents an acoustically-based analysis of the production of 
English vowels by Korean speakers. In light of Flege's (1987) finding that 
certain second language (L2) sounds that are "equivalent" or "similar" to 
those in the learner's first language (L1) are difficult to learn due to 
the lack of saliency of the differences, the paper investigated whether 
Korean speakers' success or failure to accurately produce L2 English 
vowels can be explained in terms of sound similarity or dissimilarity 
between their L1 and L2.

To establish what L2 sounds can be count as similar or new from the stand 
point of L1, Experiment I compared acoustic properties of English vowels 
/i, I, ¥å, ©¡, U, u/ as produced by native English speakers, and of Korean 
vowels /i, e, ¥å, ©©(barred i), u/ as produced by native Korean speakers. 
The target vowels were embedded in /h__d/ and /b__t/ contexts and the 
duration, fundamental frequency and frequencies of the first three 
formants were measured for the vowel in each test word. The results 
revealed that acoustic features of phonologically comparable vowels differ 
between the two languages. More specifically, there was no consistent 
difference between English /i/ and Korean /i/, English /e/ and Korean /e, 
¥å/, and English /u/ and Korean /u/; English /I/ and /U/ were "similar" 
but not identical to Korean /i/ and /o/, respectively; and English /©¡/ 
was consistently different from Korean mid front vowels.

Experiment II investigated whether the ease or difficulty of Korean 
speakers' production of English vowels can be accounted for in terms of 
the similarity and/or dissmilarity between L1 and L2 sounds as obtained in 
Experiment I. As for English /©¡/ which is a "new" vowel from the 
standpoint of Korean, the native Korean speakers succeeded at forming a 
separate category for it. English /I/, which is "similar" to Korean /i/, 
was not reliably produced distinct from /i/. These findings support 
Flege's prediction that similar but not new L2 sounds would be difficult 
to learn. As for English /U/ which is acoustically similar to Korean /o/, 
on the other hand, Korean speakers produced it as a /u/-like sound instead 
of classifying it with Korean /©©/. Thus, the results suggest that L1 
effects on the production of L2 vowels are not uniformly accounted for by 
acoustic similarities and/or dissimilarities between L1 and L2 vowels.