Final Activity Report Summary - L2SYNTAXPROD (How does L1 syntax affect bilinguals L2 production? The case of L2 agreement encoding.) During the two years of this fellowship, I conducted eleven experiments in which I investigated two main topics: (i) the encoding of agreement by native speakers and bilingual speakers; (ii) the processes of selection of syntactic structures in speech production. Our data on number agreement encoding in Basque revealed that object-verb agreement (a relation not studied before) is affected by the same syntactic factors that affect the encoding of subject-verb agreement. In other words, the number features of a noun that mismatches in number with the object noun can disrupt the encoding of object-verb agreement, inducing errors in speakers' utterances.Moreover, we showed that highly proficient Spanish-Basque early bilinguals' (L2 acquired before 4) agreement encoding is more prone to error attraction effects than that of Basque native speakers. This suggests that highly proficient bilinguals' agreement encoding rules are in some way "weaker" than those of native speakers. However, as no differences were found in their performance on subject-and object-verb agreement encoding, we can conclude that there are no differences in bilinguals' acquisition and use of subject-verb (a relation present in their L1) and object-verb (a relation not present in their L1-Spanish) agreement encoding. In sum, these results suggest that acquiring a second language at an early age allows speakers to properly acquire syntactic rules not present in their first language. However, our results also indicate that the syntactic processing of L2 agreement relations by bilingual speakers seems to be more prone to errors than that of native speakers. This suggests that the linguistic representation of a second language is "weaker" in the case of bilinguals, even when these bilinguals are highly proficient in their L2.Additionally, our results on gender agreement encoding of bilingual speakers who acquired their L2 at a late age (after 6) revealed that, in the case of antecedent-possessive pronouns or adjectives, the rules governing bilinguals' L1 gender agreement relations of possessives interfere during the encoding of agreement in their L2-English. In other words, L1 agreement rules seem to affect late bilinguals' L2 processing. Additionally, in the line with our findings from number agreement in Basque, bilingual speakers appeared to be more prone to gender attraction effects than English native speakers, suggesting that highly proficient bilinguals' agreement encoding rules are in some way "weaker" than those of native speakers. In sum, our studies on agreement encoding suggest both that bilingual speakers' syntactic processor is more prone to failure than that of native speakers, and that bilinguals' L1 syntax affects L2 processing.