How new words (don't) become memories:Lexicalization in advanced L1 Dutch learners of L2 English

It is an undisputed fact that learning – and remembering – new words is key in successful second language acquisition. And yet researching how vocabulary acquisition takes place is one of the most difficult endeavors in second language acquisition. We can test how many L2 words a learner knows, but do not know how these items were actually acquired (Cook, 2012). From L1 learning, we know that sounds can be “fast mapped” to meanings: in less than 14 minutes of passive listening to new words, neural response patterns emerge that mirror responses triggered by existing words (Shtyrov et al., 2010). The work by Gareth Gaskell and colleagues (cf. Gaskell & Dumay, 2003) has shown, however, that such rapidly formed word memories are subserved by distinct neural substrates. Only after a post-learning consolidation period, typically involving one night’s sleep, are novel words fully integrated into the existing lexicon. The most convincing evidence for this lexicalization process stems from new words competing with their lexical neighbors after the consolidation period, witnessed in longer response latencies to existing words similar in form (see also Bakker et al, 2014). It has been suggested that the speed of lexicalization depends on how many languages a person knows (Bakker et al., 2014). And yet, the question if this consolidation period works similarly in second language learners has not yet been directly investigated. This paper reports an L2 word learning and consolidation study that uses Gaskell & Dumay’s (2003) design and nonsense word list, but applies it to 30 English university majors (whose L1 is Dutch). Although the increase in response latencies to existing words in a lexical decision task is duplicated, distinct from the L1 studies are the decreases in accuracy rates over time. These outcomes pertain to L2 theorizing on how vocabulary is acquired and stored