Development of the ability to lexically encode novel second language phonemic contrasts

Second language (L2) learners must often learn to perceive and produce novel L2 phoneme contrasts. Although both research and intuition suggest that these difficulties can be overcome to some extent with exposure to the L2, it is not known what consequences this kind of learning has for the phonological structure of the L2 lexicon. We present an experiment designed to investigate the lexical representations that learners establish for L2 words that contain novel phonemic contrasts. Specifically, we consider the acquisition of Japanese consonant length contrasts by native speakers of English: Japanese contrasts consonants such as /k/ and /kk/ while English does not. The results indicate that native English speakers do not initially encode consonant length consistently in their lexical representations of Japanese words, as reflected in both listening and production tasks. However, after one year of Japanese experience, the phonological structure of their Japanese lexicon more closely approximates that of native Japanese speakers. We conclude that significant changes to the structure of the L2 lexicon can occur even within the first year of L2 learning.