The uneven advantage of multiword sequences: How idioms and collocations are processed in L1 and L2

Research has shown a processing advantage for multiword sequences (MWS) in both first language (L1) and second language (L2) speakers over novel word combinations. However, whether this advantage holds for different types of MWS for both groups is not known. We used a self-paced reading paradigm combined with a stop-making-sense task to investigate the processing of idioms used figuratively (e.g., “gray area”), idioms used literally, col- locations (e.g., “vast area”), and novel combinations (e.g., “rare area”), in both L1 and L2 speakers. In line with previous findings, both L1 and L2 speakers read collocations faster than novel word combinations. Only L1 speakers showed a processing advantage for idioms used figuratively over collocations after controlling for distributional factors (e.g., phrase-level frequency, familiarity, and contextual predictability), suggesting that semantic conventionality facilitates direct retrieval of idiomatic meanings. L2 speakers with lower proficiency did not show an advantage for idioms used figuratively but exhibited faster reading for idioms used literally over idioms used figuratively. While the meaning dominance of idioms did not exert an effect, greater idiom decomposability facilitated processing. Together, these findings indicate that, while frequency effects broadly support MWS processing, L2 speakers rely on compositional analysis in idiom comprehension more than L1 speakers.