Primability as a Predictor of L2 Alignment and Writing Performance: Evidence from a Comparative Continuation Task

Alignment refers to the tendency of interlocutors to reuse each other's language patterns during interaction, which has been regarded as a learning mechanism in second language (L2) development. Existing research has primarily examined how task-related factors shape L2 alignment, whereas much less is known about whether learner-related individual differences are associated with variation in alignment and with its subsequent learning benefits. This study examined whether learners' implicit capacity for adaptation was associated with the magnitude of L2 alignment and writing development in a comparative continuation task. Participants completed a baseline writing task, a continuation task, two priming-based measures of implicit capacity for adaptation (i.e., L1 lexical priming and L1 syntactic priming), and LLAMA_D as a supplementary measure of implicit phonological sensitivity. Results showed that sensitivity to L1 lexical priming was positively correlated with the magnitude of L2 lexical alignment, and sensitivity to L1 syntactic priming was positively correlated with the magnitude of L2 syntactic alignment. Furthermore, sensitivity to L1 syntactic priming positively predicted gains in overall L2 writing quality, accuracy, and fluency, whereas sensitivity to L1 lexical priming positively predicted gains in fluency alone; LLAMA_D was a positive predictor and sensitivity to L1 syntactic priming a negative predictor of gains in syntactic complexity. These findings highlight the role of implicit capacity for adaptation in L2 alignment and writing development, shedding new light upon individual differences in L2 learning.