L2 processing of English relative clauses and long-distance wh-dependencies: evidence from L1-French and L1-Persian speakers

The study of adult second language (L2) acquisition has sometimes resulted in theories that suggest representational deficits post-puberty. According to the Representational Deficit Hypothesis, L2 users (tend to) fail to interpret complex syntactic structures in L2 in a native-like manner since they under-use syntactic information compared to native (L1) users. However, most studies supporting a representational deficit account tend to conflate syntactic deficits with processing limitations. That is, it remains unclear if the observed non-target-like behaviour by adult L2 users reflects syntactic or processing issues. The current project aimed to investigate the nature of non-target-like L2 behaviour in English relative clauses (RCs) by L2 readers of L1-French and L1-Persian. This project opted to examine the processing of RCs to ensure the highest degree of comparability with previous research, since RCs have already been studied extensively in previous studies and the literature is replete with different accounts of the way L2 readers process and acquire English RCs. Three Studies of resumption acceptability (Study 1), RC disambiguation (Study 2), and long-distance wh-dependencies (Study 3) are presented. The results of all studies suggest that potential L1-L2 differences at an advanced proficiency do not reflect a syntactic deficit but indicate processing limitations. More specifically, in Study 1, the Persian readers resorted to an L1-based resumption strategy by accepting resumptive RCs more frequently to ease processing constraints associated with direct object and object-of-preposition RCs. However, they displayed a similar pattern of acceptability ratings as the native English and French readers with respect to the choice of relativiser used in different RC types. In Study 2, all three groups favoured a non-local over a local interpretation when RC ambiguities were presented in isolation, and when RCs were embedded in contexts, they tended towards a null interpretation (i.e., sometimes local, other times non-local interpretation). Finally, Study 3 showed that both native and L2 readers of English prioritise lexical subcategorisation over abstract syntactic information while forming long-distance wh-dependencies. Overall, the native and the two L2 groups showed similar processing behaviour across the three Studies, especially at an advanced proficiency, thus suggesting that L1-L2 differences are not qualitative in nature. Taken together, the presented Studies challenge traditional accounts of L2 acquisition and processing that suggest syntactic impairments in L2. Instead, this project suggests the ability to process complex syntactic structures such as RCs remains intact in an L2, and the observed deficits in the past are likely the result of L1, proficiency, and working memory constraints.