In this paper I provide cross-linguistic evidence for a functional projection between D and NP, which I call “Number Phrase” (NumP). In a full noun phrase, the head of this projection is, among other things, the locus of number specification (singular or plural) of a noun phrase. Pronominal noun phrases are distinguished from full noun phrases by the fact that they lack a lexical projection, i.e., they lack a NP. The existence of two distinct functional categories predicts the existence of at least two classes of pronouns, those of the category D, and those of the category Num. In both Modern Hebrew and Haitian, there is evidence that this prediction is borne out.

Stowell (1981) demonstrates that nominal phrases in VP or PP are subject to certain constraints which are not pertinent in the domain of NP or AP. Nominal phrases in VP or PP are obligatory and they must be realized in a position which is adjacent to the head of the phrase (i.e., in a phrase marker; “V° NP” or “P° NP”). In contrast, nominal phrases in NP or AP are optional and do not have to be adjacent to the head. There is a systematic exception to this generalization in the lexically determined class of nouns known as Bare NP adverbs (cf. Larson 1985). Nominal phrases headed by one of this class of nouns appear optionally in VP and they are not required to be adjacent to the verb.

Many theorists (e.g., Hyams 1987; Pinker 1984) working in the framework of generative grammar have assumed the “Continuity Hypothesis”. Under this view language acquisition is made up of a series of continuous stages. The child moves from one stage to another, and at each stage the grammar posited by the child is determined by Universal Grammar (UG). The motivation for the movement from one stage to another comes from a trigger in the language environment which causes the child to restructure her grammar, and so move on to the next stage. The Continuity Hypothesis has provided an explanation for the acquisition of many linguistic structures; however, in many instances it has been difficult to explain exactly which data in the language environment act as a trigger, and why they have an effect on the child’s grammar.

Current linguistic theory offers a highly detailed account of what linguistic competence consists of, as well as an indication of how that competence is acquired by L1 learners, via an innate Universal Grammar (UG). In second language (L2) acquisition, a major issue is the nature of the L2 learner’s competence and the degree to which it is similar to or different from the competence attained by native speakers. A theory of linguistic competence is essential to our understanding of what L2 competence might consist of, and should inform L2 acquisition research (Gregg 1989). In this paper, I will adopt certain recent proposals concerning verb movement and the functional categories Agreement and Tense (Chomsky 1989; Pollock 1989), and investigate whether these proposals can provide a suitable explanation of the linguistic behaviour of French learners of English.