The impact of learning new meaning on the previously learned meaning of L2 ambiguous words: The role of semantic similarity

Previous study has found that previously learned meaning affects the learning of new meaning for known second language (L2) words. However, it is not clear whether learning a new meaning also affects the previously learned meaning and whether this effect is modulated by the semantic similarity between them. The current study aimed to explore this issue using event-related potential technique. A word learning task was used, in which Chinese-English bilinguals were required to learn a new meaning that was semantically related or unrelated to the previously learned meaning of familiar L2 words and judge the semantic relatedness between the trained word and a probe word in the same trial. The results showed that both the N400 and late-positive component (LPC) amplitudes for probe words in the unrelated new meaning condition were significantly different from the unlearned condition, which suggests learning new meaning interferes with accessing the previously learned meaning. Moreover, significantly less positive LPC was found in the unrelated new meaning condition relative to the related new meaning condition, showing a mediation of semantic similarity in the perturbation effect. We conclude that learning L2 new meaning has a backward interference effect on accessing the previously learned meaning and this effect is modulated by semantic similarity. These findings provide supporting evidence for the interaction mechanism of learning the multiple meanings of L2 ambiguous words.