Effects of vocabulary acquisition on lexical competition in speech perception and production.

Three experiments examined the roles of time and exposure

frequency in lexicalization of novel words. Participants

learnt novel items (e.g., cathedruke) of varying frequency

that overlapped with existing words (e.g., cathedral). The

effect of learning on lexical competition was tested by

measuring responses to the existing words. In lexical

decision (Experiment 1), low frequency novel items

facilitated responses to existing words immediately after

exposure, but had no effect a week later, whereas high

frequency items produced inhibition both immediately and

a week later. The inhibitory effects indicated that the novel items had engaged in lexical competition. In single word shadowing (Experiment 2) and naming (Experiment 3), all

effects were facilitatory, suggesting that the main impact in these cases was on speech production. We interpret these

results in terms of the influence of vocabulary acquisition

on the competition processes involved in speech perception

and production.