Sign language vocabulary learning: uncovering fast cross-language interactions between signs and words

This study explores bimodal cross-language interactions in the context of sign language vocabulary learning. Specifically, whether such interactions occur during oral language production, and whether they extend to an oral language not directly used in the training. Across three sessions, hearing Catalan-Spanish non-signers were trained on Catalan Sign Language (LSC) signs through an associative learning task (LSC-written Catalan). Participants subsequently performed an LSC-to-Catalan prime translation task with primes written in Catalan or Spanish. The primes were either phonologically related or unrelated to the target signs via their LSC translations. Behaviourally, LSC phonologically related word primes elicited faster translations, regardless of the prime language. Conversely, the N400 ERP component showed prime language-dependent effects. N400 differences were initially limited to Catalan, the training language, and extended to Spanish by the third session. These findings highlight the dynamic interplay between oral and sign languages during early sign language learning.