The development of the syntax-information structure interface
Recent acquisitional studies reveal that formal properties at the lexicon-syntax interface are in place before discursive properties at the syntax-discourse interface. It has been argued that this phenomenon results from learners’ deficits with <i>interpretable </i>discursive features like [focus]. This study claims that the phenomenon derives from learners’ deficits with the <i>un-interpretable </i>formal features responsible for regulating the occurrence of discursive focus, whereas learners’ representation of <i>interpretable </i>focus features are intact. This claimwas tested by conducting a study with Greek learners of non-native Spanish at three proficiency levels. Learners judged Subject-Verb and Verb-Subject order with intransitives (unergatives and unaccusatives), which is constrained both formally (Unaccusative Hypothesis at the lexicon-syntax interface) and discursively (presentational focus at the syntax-discourse interface). Results confirm that, while the general ‘syntax-before-discourse’ observation is correct, learners’ source of persistent deficits with discursive properties derives from the <i>uninterpretable </i>feature that regulates the syntactic realisation of focus. This implies that learners are sensitive to the (interpretable) [focus] feature, but are unable to grammaticalise it syntactically.