This chapter examines to Patty's acquisition of some of the categories and features associated with nouns and noun phrases, particularly the features of number and definiteness. It discusses an interesting interaction between number marking and definiteness in Chinese that could hypothetically pose a transfer problem that Patty appears to have overcome. For English, the chapter considers that nominal phrases are actually nominal determiner phrases (DPs) headed by the functional category determiner, which selects a noun phrase as a complement. In short, there is nothing in the data to suggest that Patty has not acquired a nativelike representation for the essential word order of English DPs. The proportion of suppliance of plurals in unquantified obligatory spoken contexts is roughly similar to that for quantified expressions, although the number of contexts in the spoken data is considerably smaller, making comparisons difficult. There are many contexts where it is difficult or impossible to determine the obligatoriness of singular versus plural usage.