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.
But how can we explain these perceived relationships? It is certain that if we define word categories in individual terms, say by just listing possible categories, then any explanation of the categories themselves or their relationships will be impossible. An analogy might serve to make the point clearer. Suppose that biologists had never thought of categorising living things into taxonomic groups and instead simply identified individual sub-species such as ladybirds, field mice, pythons, etc. From this perspective it would be impossible to answer questions such as why do ladybirds and bluebottles both have six legs and wings? At best, biologists would only be able to claim that this was an accidental chance happening. Once there is a taxonomic system, such questions are easily answered: ladybirds and bluebottles are both insects and all insects have six legs and wings. The same is true for word categories. If we merely identify categories such as nouns, verbs and determiners, we cannot explain relationships between the categories.
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.
Other features that have been proposed include [±N] and [±V], first suggested by Chomsky (1970). The ‘N’ and ‘V’ used in these features obviously do not stand for noun and verb as these categories are to be defined by these features. However, the fact that nouns are categorised as being [+N] and verbs as [+V] indicates that these features are meant to have something to do with these categories. To some extent, it is irrelevant what the features ‘mean’. The important point is which categories share which features and hence have something in common and which have different features and hence are distinguished. From this perspective we could have used features such as [±1] and [±2].
Consider now the intuition that nouns and verbs are diametrically opposed categories. We can account for this if we assume that they have exactly the opposite features to each other. We have said that nouns are categorised as a [+N] category and so verbs must be [–N] if we are to maintain that they oppose nouns. Similarly, as verbs are [+V], nouns must be [–V]. We therefore categorise nouns and verbs as the following:
| (24) | nouns | = | [–F, +N, –V] | |
| verbs | = | [–F, –N, +V] |
Note, both nouns and verbs are thematic categories and hence they share the [–F] feature, but in every other way they differ.
How can we capture the sense that determiners have something in common with nouns and modal auxiliary verbs have something in common with verbs, even though one of these pairs of elements is function and the other is thematic? The answer is fairly easy. The pairs may differ in terms of the [±F] feature, but they are similar in terms of the [±N] and [±V] features:
| (25) | determiners | = | [+F, +N, –V] | |
| modals | = | [+F, –N, +V] |
In other words, determiners are the functional equivalents to nouns and modals are functional verbs.
To develop the system a little further, consider the intuitions that adjectives seem to have something in common with nouns, as they are typically used to modify nouns, as in crazy kid or thoughtful suggestion, but they also seem to have something in common with verbs, as they have certain distributional properties in common:
| (26) | a |
Rick is { |
rich running |
} |
| b | the { | rich running | } robber |
In this example, rich is an adjective and running is a verb and obviously they can both appear in similar environments. But if nouns and verbs are diametrically opposed to each other, how can adjectives be similar to both? The answer is that adjectives share different features with both nouns and verbs. Thus, we may categorise both nouns and adjectives as [+N] and both verbs and adjectives as [+V] and in this way adjectives will share features with both nouns and verbs. Of course, they will also have features different from nouns and verbs, but as we do not want to categorise adjectives as the same as the other categories, this is a positive aspect of this proposal. Adjectives can therefore be categorised as:
| (27) | adjectives | = | [–F, +N, +V] |
| (28) | N | ||||
| + | – | ||||
| V | + | adjective | verb | ||
| – | noun | ? | |||
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:
| (29) | prepositions | = | [–F, –N, –V] |
However, this cannot be put down to good fortune. After all, categorising elements in terms of these features has consequences concerning what other categories are related to or different from these elements. Note that the feature combination in (29) predicts that while prepositions differ from nouns in that they are [–N], they are similar to nouns in that they are [–V]. Similarly, prepositions differ from verbs in being [–V], but they share the [–N] feature with them. Thus prepositions are predicted to be similar to nouns and verbs, but in a different way to how adjectives are similar to these categories. Indeed, while prepositions do not have similar distribution patterns as verbs, as do adjectives, they share another property with verbs. Consider the following observations:
| (30) | a | see him | |
| b | to him | ||
| c | *portrait him | (portrait of him) | |
| d | *mindful him | (mindful of him) |
In (30), we see that both verbs (see) and prepositions (to) can be followed by a word such as him, which is a pronoun. Nouns (portrait) and adjectives (mindful) cannot. We might claim therefore that the ability to be followed by a pronoun is restricted to the [–N] categories. Now consider the following:
| (31) | a | it was Sally that Sam saw |
| b | it was underneath that I found the treasure | |
| c | *it was stupid that Steve seemed | |
| d | *it was fishing that Fred went |
As shown in (31), a noun like Sally and a preposition such as underneath can sit in the position between the words was and that in this English construction, known as a cleft construction. However, an adjective (stupid) and a verb (fishing) cannot occupy this position. We might claim therefore that this position can only be occupied by [–V] categories.
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.
We can re-draw the typology given in (23) using the three features in the following way:
| (32) |
A further advantage of this system is that it places restrictions on what categories we can suppose to exist, hence increasing its explanatory power. For example, we would not be entitled to come up with an extra category without destroying the system developed. One way to add extra possible categories within the system would be to declare another binary feature. But this would not allow the addition of one extra category, but a further eight! Moreover, these extra categories would have to be shown to be related and opposed to the existing categories in the same way that these are related and opposed to each other.
Another way to extend the system, which we will be making some use of, relies on the notion of underspecification of features. All the categories discussed above are fully specified for all the features, so each is associated with a plus or minus value for all three features. Underspecification is a situation in which one or more features is not specified for its value. Thus, we might propose a new category [+N, –V] which is not specified for the [±F] feature. This category would then be a noun which is neither functional, nor thematic. We will see that there is evidence that the [±F] feature can be left underspecified and hence there are a further four ‘non-functional’ categories. We will introduce these categories in the following sections. The important point for the moment is that the system of features restricts our ability to invent new categories ‘willy-nilly’.