Learners' Proficiency and LexicalEncoding of the Geminate/Non-geminate Contrast in Japanese

Every speaker of a language stores the pronunciation of the words in his mental lexicon, so that each word is phonologically represented in the lexicon. Such lexical representations for words in a second language (L2) can be much less precise than for the native language, mostly because of misperception of the L2 phonemes (e.g., Pallier, Colomé, & Sebastián-Gallés, 2001). Hence, L2 lexical representations can be confusable or ambiguous, yielding spurious homophony (two different words will have the same representation) and spurious lexical access. For example, near-words can be mistaken as real words (e.g., */lɛmp/ for /læmp/ lamp, Broesma & Cutler, 2008; Dupoux, SebastiánGallés, Navarrete, & Peperkamp, 2008; Sebastián-Gallés, Echeverría, & Bosch, 2005). Furthermore, previous studies revealed that lexical access in L2 can be asymmetrical according to Cutler, Weber, and Otake (2006) and Weber and Cutler (2004); they looked at learners of English whose native language was Dutch. Dutch only has a mid-front vowel in its inventory. Thus, there is no contrast between a mid-front vowel as in pen /pɛn/ and a low front vowel as in panda /pænda/. The study showed with eye-tracking that fixations for targets containing a similar phonological category to learners’ first language [L1] (/pɛnsɪl/) were more selective (earlier decrease of looks to the competitor with a new phonological category, i.e., a phoneme which does not exist in learners’ L1) than fixations for targets containing a new category (/pænda/; later decrease of looks to a competitor with a similar category to learners’ L1). Concretely, upon hearing an auditory prompt syllable (/pɛn./ vs. /pæn./), Dutch L2 English listeners fixated the target (/pɛnsɪl/) and successfully avoided looking at the competitor (/pænda/) earlier than in the opposite case, when the target contained a new, unfamiliar category (/pænda/). In this case, the fixations to the competitor (/pɛnsɪl/) along with the target were present for a longer period of time while hearing the auditory prompt. These findings suggest that when listeners hear a familiar category, their lexical activation is more specific, perhaps because words containing this sound are more clearly represented. When listeners hear the unfamiliar (i.e., new) category /æ/, they activated both the target and competitors more strongly, perhaps because the word representations containing this unfamiliar category are not represented in a target-like way. If the contrast between /æ/ and /ɛ/ was merged in lexical representations, fixations would be symmetrically (non)selective. Weber and Cutler’s (2004) data therefore suggest that these two categories are not merged in lexical representations, unlike in the cases described by Ota, Hartsuiker, and Haywood (2009) or by Pallier, Colomé, and Sebastián-Gallés (2001). A possible cause of these effects is that L2 learners’ lexical representations are fragmentary: although dominant and non-dominant categories are encoded separately (hence, lexical separation is achieved), the non-dominant category is perhaps represented as a poor match of the dominant category (Hayes-Harb & Masuda, 2008). Of note, the asymmetries reported by Weber and Cutler (2004) have been obtained with highly proficient Dutch L2 learners of English, who had no serious difficulties making a perceptual distinction between /ɛ/ and /æ/, a contrast not present in Dutch.