Abstract
A current debate in second language (L2) phonological learning is how learners acquire categories (long-term memory representations) for L2 segments (vowels and consonants). Some research suggests that learners acquire these categories on a phonetic or segmental level, learning the sound independently of factors such as the lexicon (Flege, Frieda, Walley & Randazza, 1998). Their findings suggest that segmental related factors such as the similarity between first and second language sounds (cross-language similarity) or phonetic context play the most important role in whether and how L2 segments are acquired. Other research, however, suggestd that learning L2 segments is similar to how children learn a first language (Walley & Flege, 1999): children seem to learn the correct pronunciation for segments by first learning the correct pronunciation for words (Beckman & Edwards, 2000; Werker & Tees, 1999). If this is the case, then L2 children and adults should more accurately produce segments in some words than others and their productions should be influenced by aspects of the lexicon, such as word frequency and word familiarity.
This study first relooks at previous research by examining how lexical factors such as word frequency, word familiarity, and imagability affected the production and perception of words by different groups of L2 learners (native adult English speakers learning French vowels, native child Spanish speakers learning English vowels, and speakers of several first languages learning English word stress).
Next, this study focuses on how two segmental or sound-related factors (cross-language perceptual similarity, syllabic context) as well as two lexical or word-related factors (word frequency, subjective word familiarity) influenced the production of eight English vowels by 40 Korean children and adults exposed to English in the U.S. for an average of 1 and 7 years. Results revealed that lexical factors affected adults' second language (L2) production more than children's and depended (at least for adults) on amount of L2 experience. Lexical influences on L2 production were obtained when segmental influences were particularly strong (for dissimilar L2 vowels or vowels in "difficult" syllabic contexts) and when learners lacked extensive experience with the L2 (within 1 year of L2 experience). These findings suggested that learners' experience with the L2 lexicon (becoming familiar with more words, perhaps through frequent exposure to them) may help learners overcome native language constraints on L2 phonological learning, but also underscore the complex relationship between segmental and lexical factors on L2 pronunciation learning. These findings also demonstrate differences between child and adult L2 learning.