There are three main types of Noun Phrase and paradoxically two of these types consist of phrases which are degenerate in the sense that they consist of single words - Pronouns and Proper Names because words of these types are grammatically acceptable as the subjects of sentences. For simplicity of the modelling we will henceforth consider pronouns and proper names as types of noun phrase. The other type of noun phrase takes a number of forms but does actually contain a noun and for technical reasons is known as type 'N-bar-bar' .

By way of illustration for the model of N-bar-bar consider the phrase The wildly yapping dog on the sofa. We can annotate the types of word and constituent phrase are as follows:

In our earlier example the noun phrase which was the subject of our sentence is analysed like this:

The model is shown in figure 7.