1.3 A Typology of Word Categories

Having introduced some of the basic concepts, let us now turn to look at what categories we need to refer to in the description of a language like English. In generative linguistics it is often seen as a positive aim to keep basic theoretical equipment to a bare minimum and not to expand these unnecessarily. This can be seen in the standard approach to word categories in terms of the attempt to keep these to as small a number as possible. In the present book we will mainly be concerned with eight basic categories. These come in two general types: thematic categories and functional categories. In the thematic categories we have verbs (V), nouns (N), adjectives (A) and prepositions (P) and in the functional categories there are inflections (I), determiners (D), degree adverbs (Deg) and complementisers (C). Thus we have the following classification system:

1.3.1 Categorial features

Before we start to look at the properties of individual categories, we will make the typology of categories described in (23) a little more systematic. One might wonder why there are these categories and why their division is so regular: four thematic categories and four functional ones. Moreover, we may have the feeling that the categories given in (23) are not completely unrelated to each other. For example, it is often felt that nouns and verbs are somehow opposites of each other or that adjectives have some things in common with nouns and other things in common with verbs. Even across the thematic/functional divide, we may see similarities. For example, words like the, these and some are determiners and these seem more related to nouns, which they usually accompany, than to verbs. Modal auxiliary verbs, such as may, can and must, which as we will see are classified as belonging to the inflections, are obviously more closely related to verbs than nouns.

1.3.1 Categorial features

One way to impose a system on elements is to use a set of features to distinguish between them. Each category can then be defined in terms of a unique collection of these features, but they may share some of the features with other categories, accounting for similarities between them. In linguistics, binary features, i.e. those which can be valued in one of two ways (plus or minus), have been found useful for producing systems of categorisation. For example, we might propose a feature [±F] (‘F’ to indicate functional) to distinguish between the thematic and functional categories. All thematic categories would possess the [–F] feature and all functional categories would possess the [+F] feature. In this way we can immediately distinguish between the two groups and account for why certain categories are similar to others in terms of which feature they possess.

1.3.1 Categorial features

Note, both nouns and verbs are thematic categories and hence they share the [–F] feature, but in every other way they differ.

1.3.1 Categorial features

This is fortunate as there is one more thematic category left to be included into the system: the prepositions. Thus we can claim that prepositions fill this slot:

1.3.1 Categorial features

We see from the discussion above the predictive power of the system that we have set up: the system predicted that there should be a fourth thematic category that has certain properties and these fit the category of prepositions very well. We can take this as evidence in favour of this system of features. What else does the system predict? It is clearly predicted that if we add a third binary feature to the two we have just been discussing, then a further four categories will be defined. This again matches perfectly with the description of categories we started this section with, as seen in (23). With the third feature, [±F], there should be four functional categories which match the four thematic categories in terms of their feature settings for [±N] and [±V]. We have already seen how determiners and modals can be analysed as functional nouns and functional verbs, respectively. The expectation is that degree adverbs, such as so and too, and complementisers, such as that and if, should be related to adjectives and prepositions in the same way. As degree adverbs modify adjectives in a very similar way to how determiners modify nouns, it is not difficult to conclude that degree adverbs are functional adjectives. This leaves complementisers to fill the final place as functional prepositions. There is evidence in favour of this assumption, but it rests on notions not yet introduced, so we will have to wait until later to demonstrate it.

1.3.2 Predicates and arguments

To understand the difference between thematic and functional categories we first need to introduce concepts to do with how the elements of a sentence can be related to each other. Take a simple sentence:

1.3.4 The Thematic categories

1.3.5.1 Inflections

Given that inflection is a functional category and takes no part in thematic structure, members of this category do not have theta grids as part of their lexical entry. Furthermore, their subcategorisation seems to be much simpler than any thematic category: all inflections are always followed by a verbal element and hence we might suppose that they all subcategorise for verbal complements:

4.4 Conclusion

In this chapter we have introduced the structure of the DP, the projection of a functional category. We will contrast this in the next chapter with the VP, which is obviously the projection of a thematic category. As far as the X-bar structure is concerned, the two are very similar. But, as we know, lexical properties have a very strong influence on structure and hence we might expect that the phrases headed by functional and thematic heads will differ to some extent.