Productive inventory and case/agreement contingencies: a methodological note on Rispoli (1999)

Rispoli (1999) suggests that previous studies arguing for a contingency between the case of subject pronouns and the presence/absence of verbal agreement in the acquisition of English (e.g. Schütze, 1997) suffer from methodological problems, and presents new data that fail to support earlier findings. I show that Rispoli's methodology unnecessarily biases his study against finding the predicted contingencies: it fails to take account of children's productive lexical inventory of pronoun forms. As a result, syntactic versus morphological sources of error fail to be distinguished. I explain why this distinction is crucial within the AGR/Tense Omission Model, and clarify its predictions.