How Much Do We Imitate in a Non-Native Language? Explicit Versus Implicit Imitation in L2 Speech

Previous research on imitation in L1 has shown that explicit instructions generally generate more robust convergence with the model talker than implicit instructions. However, this regularity has not gained sufficient empirical attention in L2 speech imitation. To address this gap, we examined English vowel duration variability as a cue to following voiced versus voiceless consonants (vowel clipping) in 28 Czech and 28 Polish L2 learners of English. Neither Czech nor Polish uses vowel clipping as a voicing cue in the L1. Participants completed three tasks: (1) baseline, (2) imitation, and (3) post-test. Our results confirmed convergence towards the model stimuli during imitation, but this effect diminished in the post-test. The critical manipulation involved the imitation task: half of the participants were explicitly instructed to imitate the model voice as accurately as possible (explicit imitation), whereas the other half performed a simple oral identification task (implicit imitation). Contrary to predictions based on L1 imitation studies, explicit instructions did not increase the magnitude of convergence in L2 learners in our study. Moreover, the results showed that the Czech and Polish participants exhibited comparable degrees of convergence with the native English model, thus replicating the null effect of instruction type across two language groups. We discuss the current results by offering two lines of reasoning as to why explicit instructions did not, in our study or more generally, lead to more imitation in L2 speech.