In a recent commentary, Grinstead (2000) argues against Bates & Goodman's (1999) claims that the development of grammar is contingent on developments in the lexicon, and that, therefore, there is no need for an independent grammar domain. Citing data on the acquisition of negative commands in Catalan and Spanish, Grinstead argues that beyond grammatical elements that are linked with lexical items, there must also exist independently a computational component, which includes grammatical constraints. He argues further that these constraints are observed from the beginning of acquisition. The purpose of this note is, first, to challenge the evidence Grinstead brings to bear in support of this position and, second, to argue further that the acquisition of negative commands in Spanish is better understood in terms of item-based learning combined with low functional load.