Similar forms with different functions. The (un)learning of the Italian periphrasis andare a + infinitive by L1-Spanish speakers

Despite their formal similarity, the Italian periphrasis andare a "go to" + infinitive and the Spanish periphrasis ir a "go to" + infinitive display different values. In this paper, we investigate how Spanish (L1) speakers acquire andare a + infinitive when learning Italian as a second language (L2). This case study offers a good van- tage point from which to observe the interaction between learning (values that are present in L2 but not in L1) and unlearning (values that are present in L1 but not in L2) in the acquisition of L2 forms that are structurally but not functionally similar to L1 forms. An experimental study based on acceptability judgements shows that while a long and intense exposure to the L2 input allows both learning and unlearning, L2 instruction not focused on the two periphrases and with little exposure to input is less successful: unlearning of non-target values is only reached by advanced speakers, who moreover generalise the inhibition of the L1-transfer to values that are accepted by native speakers. This suggests that in cases like the one under investigation here a focused pedagogical intervention may be useful.