The present paper reviews previous studies in visual word recognition with a special focus on lexical competition and discusses its applicability to second language (L2) vocabulary acquisition research. Lexical competition refers to a phenomenon that slows down the process of visual identification of words, which is assumed to happen as a result of pre-activation of lexical representation of the word in question and its orthographic neighbors.
Previous research in first language (L1) visual word recognition has shown that when an orthographically similar word is used as a prime in a masked form-priming lexical decision experiment, the processing of the target is inhibited (i.e., slowed down) whereas when an orthographically similar nonword is used, the processing is facilitated (i.e., speeded up). This effect of prime lexicality has been explained by the lexical inhibition hypothesis. It posits that the presentation of an orthographically similar word prime activates its own (prime) and neighbor’s (target) representation in the mental lexicon, which causes lexical competition between them that ultimately results in lexical inhibition. In contrast, the presentation of an orthographically similar nonword prime does not cause this effect because nonwords are, by definition, non-existent in our lexicon.
The prime lexicality effect and lexical inhibition phenomenon have an important implication when it comes to L2 vocabulary acquisition. When we ask learners to learn new L2 words, if we could observe the lexical inhibition effect in a masked form-priming experiment in which the learned words are used as primes, it should be good evidence to claim that the representations of the new words are established in the learners’ mental lexicon. Otherwise, the newly learned word primes should behave like nonword primes, and so we should observe a facilitative priming effect.
So far only a few studies have investigated this possibility in L2 vocabulary acquisition research. But since the use of the lexical competition phenomenon is an interesting and promising way to evaluate learners’ L2 vocabulary acquisition, more research is expected in the future.