Focus and split-intransitivity: the acquisition of word order alternations in non-native Spanish

Recent unrelated studies reveal what appears to be a common acquisitional pattern in second language acquisition (SLA). While some findings show that advanced learners can indeed achieve convergent, native-like competence with formal syntactic properties (even when these are underdetermined by the input), other findings suggest that they can display divergent and even optional competence at the syntax-discourse interface with discursive properties like focus and topic. These apparently contradictory observations are not coincidental, as they can also be traced in other acquisitional studies on L1 acquisition, L1 attrition in bilinguals, child SLA and SLI (specific language impairment). If this pattern is correct, it should be observed in the L2 acquisition of any given property that is simultaneously governed by both a formal grammatical constraint and a discursive constraint. I tested whether this is the case in advanced non-native Spanish acquisition of the syntactic distribution of subject-verb (SV) and verb-subject (VS) word order, which is constrained by both a formal syntactic property (the Unaccusative Hypothesis or Split-intransitivity Hypothesis) and a property at the syntax-discourse interface (presentational focus). Results show that the interlanguage grammars (ILGs) of both English (n = 17) and Greek (n = 18) learners of Spanish converge with the grammars of native Spanish speakers (n = 14) when formal properties are involved, yet they diverge (in particular by showing optionality) with discursive focus. These results confirm the emerging view that acquisition of formal syntactic properties is more readily acquired than discourse properties, which are persistently problematic.