The effect of construction frequency and native transfer on second language knowledge of the syntax-discourse interface

This article investigates knowledge of discourse-conditioned left dislocations in the interlanguage competence in Spanish and English second language learners. Although Spanish clitic left dislocation (CLLD) and English topicalization are functionally very similar, they differ in that the former but not the latter requires the dislocated phrase to be clitic doubled. In contrast, the fronted focus (FF) construction is functionally and syntactically similar in the two languages. Two experimental studies investigated knowledge of the syntactic form and discourse appropriateness of CLLD and topicalization, using knowledge of FF as a baseline. English-native learners of Spanish were successful in acquiring CLLD as well as FF. However, Spanish-native learners of English demonstrated no knowledge of English topicalization even at near-native levels of proficiency, whereas they did well on the transferable FF. These results are examined in the light of the interface hypothesis. It is argued that construction frequency in the input and transfer from the native language, but only those two factors together, can explain the experimental results.