Adverb position in heritage and L2 Spanish-English code-switching

This study examines adverbs in intraclausal code-switching among late L2 Spanish bilinguals and heritage speakers of Spanish. Spanish allows adverbs pre-verbally and post-verbally, while English restricts adverbs to pre-verbal position. Previous research has shown that the language of the adverb predicts acceptability in code-switching contexts, with English adverbs allowed only pre-verbally and Spanish adverbs allowed in both positions. This study extends this work to L2 bilinguals, an understudied group in terms of code-switching acquisition. Using a written acceptability judgment task, 73 bilinguals rated code-switching stimuli involving verb-adverb switches, as well as monolingual versions of those sentences. Results showed that all groups preferred pre-verbal adverbs in English, regardless of whether the sentence was switched or completely in English. As for Spanish, participants accepted complement-type adverbs in either position, while specifier-type adverbs patterned like English, being accepted only preverbally. Crucially, there were no significant differences found between the heritage speakers and the two bilingual groups, which varied in terms of L2 Spanish proficiency. These findings suggest that the language of the adverb drives acceptability, and that all bilingual groups follow similar structural constraints. Thus, the acquisition context (heritage vs. L2) does not significantly impact adverb positioning in Spanish-English code-switching.