Case, inflection and subject licensing in child Catalan and Spanish

The development of specified tense and number morphology in child Catalan a nd Spanish is found to correlate with the onset of overt subject use. The d ata come from four monolingual child Catalan-speakers (from the Serra & Sol e corpus) and one monolingual child Spanish-speaker (from the Linaza corpus ) who were studied longitudinally from I:0 to 3;6, approximately. The simul taneous emergence of tense and number morphology on one hand and overt subj ects on the other in the children's speech is taken as evidence that a part icular aspect of Universal Grammar, Case Theory, determines the possible co -occurrences of verbal inflections and subject types in developing grammati cal systems. Parallels in verbal inflectional development are found in othe r child languages, while such parallels are not found in regard to subject use. Possible modifications to Case Theory, which would allow a unified acc ount of the cross-linguistic developmental patterns of subject use, are con sidered. The possibility of explaining the early absence of overt subjects in these null subject languages as the result of an early sentence processi ng deficit is explored and rejected. The children's knowledge of whether th eir language is a null subject or overt subject language even before acquir ing adult-like verbal inflection is taken as further evidence for what has been called 'early convergence' on parameter settings.