Processing constraints on L1 transfer

This chapter focuses on the interplay between first language (L1) transfer and psycholinguistic constraints on second language (L2) processability. The theoretical assumptions underlying this chapter are those made in processability theory (PT) (Pienemann, 1998), which include, in particular, the following two hypotheses: (a) that Ll transfer is constrained by the processability of the given structure, and (b) that the initial state of the L2 does not necessarily equal the final state of the L1 because there is no guarantee that the given L1 structure is processable by the underdeveloped L2 parser. In other words, it is assumed that L1 transfer is constrained by the capacity of the language processor of the L2 learner (or bilingual speaker) irrespective of the typological distance between the two languages. Using the PT hierarchy as a comparative matrix, we demonstrate on the basis of empirical studies of L2 acquisition that learners of closely related languages do not necessarily transfer grammatical feature at the initial state even if these features are contained in Ll and L2, providing the features are located higher up the processability hierarchy. We further demonstrate that such features will be transferred when the interlanguage has developed the necessary processing prerequisites. In addition, we demonstrate that typological distance and differences in grammatical marking need not constitute a barrier to learning if the feature to be learned is processable at the given point in time. All of this demonstrates that processability is a key variable in L1 transfer.