L3 learners may pick what they need: [Gender] and [number] agreement in L3 Portuguese

To determine the source of transfer in third language acquisition (L3A), we tested the effects of typology and L2 proficiency of L1 English-L2 Spanish learners in the initial stages of L3A of Portuguese. We tested learners’ knowledge of [gender] and [number] features in both their L2 and their L3 through grammaticality judgment tasks and elicited production tasks. We found that L3 learners transfer only some features, specifically [gender] rather than [number], suggesting that there was partial transfer from the L2 but not wholesale transfer of either the L1 or L2. This interpretation supports models of L3A transfer that pick-and-choose features, like the Scalpel model, over wholesale transfer, like the Typological Primacy Model. We also found that facilitative transfer of L2 features occurs only after a threshold acquisition of the relevant features, in support of the Threshold Hypothesis. We did not find that per se L2 proficiency was predictive of L3 performance though. The Threshold Hypothesis suggests L3 proficiency interacts with typology after a certain threshold is achieved but does not specify whether per se proficiency must be attained or acquisition of the relevant features. We interpreted these results as showing an interaction between the Threshold Hypothesis and the Scalpel Model.