This study investigates regressive cross-linguistic influence (rCLI) from developing third language (L3) Norwegian, Swedish, or Danish to advanced second language (L2) English among first language (L1) Polish speakers. We focus on three phenomena related to second position finite verb placement (V2), differing in frequency and input ambiguity: V2 with adverbial fronting, V2 with object fronting, and adverb placement in main clauses. Using three tasks targeting comprehension and production – an acceptability judgement task, a self-paced reading task, and an oral production task – we compare two groups: L3 ( n = 163) and L2 learners ( n = 71) matched in L2 English proficiency. We found modest but consistent evidence for rCLI: compared to the L2 group, L3 learners were more likely to accept V2 items, were less sensitive to V3 violations, and produced occasional instances of V2. Structure-specific rCLI emerged only in the judgment task, with the strongest effects in V2 with adverbial fronting, weaker effects in adverb placement, and no effects in V2 with object fronting. Extending the Linguistic Proximity Model to rCLI, we argue that the underlying mechanism is the same as in progressive CLI: co-activation. However, because L2 grammars are more stable and less underspecified than a developing Ln, co-activation does not lead to L2 grammar restructuring.
Olszewska et al. (Sat,) studied this question.