The present study looks at the effects of structural similarities between L1 and L3 on
learner performance. The main focus is on the knowledge of the dative construction in Polish
learners of Portuguese. Portuguese and Polish share a number of important similarities in their
use of the dative, which include functions not found in English, the learners’ L2. The main
question investigated in this study is whether learners are aware of the non-banal similarities
(given that they do not occur in English) and whether they can make use of that knowledge.
It is found that learners do benefit from positive transfer, but that depends on the kind of
function and frequency of the dative