Definitions of Word Classes (05-Feb-2004)

Why study syntax? One reason is to help with understanding in diseases that have affect on language (aphasia); it is also of interest for people studying linguistic style (e.g. in different types of written text). We can also see that over time, the syntactic rules of English have changed, so that in Chaucer's time, the following two statements were valid:

But the following was not (and is not now) valid:

To do syntactic analysis, we need to know what classes of words exist (e.g. nouns, verbs), because syntactic structure is built of phrases made up from words from certain grammatical categories, in the same way that words are built from morphemes in certain structured ways.

Traditional definitions

Traditional definitions can be helpful, for example "The verb in a sentence is the word that is most concerned with the action". But in this sentence, the word most concerned with action is "action", although we know (perhaps using morphological criteria) that the verb is "is". So there are other criteria too: this definition itself is not sufficient.

There are converging criteria for word category membership: semantics (i.e. traditional definitions) may help, but we may need to use morphological criteria as well. E.g. in

we notice that all of the alternate words receive the same (morphologically speaking) inflection : "~s". And there is a certain set of words which can receive a ~s inflection in a certain context. But other words, e.g. "between", "red" cannot get put into that context. So we can form groups of words, regardless of their semantic meaning, which can be classified according to where they can fit into a phrase and the kind of inflection they get.

There are exceptions, e.g. in the case of nouns, we can see that

All but "fish" take a "~s" affix, but we still know that "fish" can fit in this place in the phrase: it wouldn't be sensible to use "between" at this point for example.

So it's possible to form groups of related words, for example
Group 1   Group 2
her friend
his attitude
their action
such jokes

These pairs are co-predictive: we can predict that any word from Group 1 will be able to join on to any word from Group 2 (at least syntactically). The way that free morphemes can be joined together is what syntax is. What is of interest is how we assign names to "Group 1" etc..

Verbs

Traditionally, the name for words such as uses/drives/has/needs/knows/wants is "verb". Certain syntactic and morphological rules apply to "verbs":

So the slot in "she xxxx it" can accept a verb (syntactically), and the verb that goes in there will obey certain morphological constraints.

Verbs in English behave very regularly, e.g. they always have a past form. So a good test of whether a word is a verb is to see whether it can be inflected to form a past tense version.

Nouns

For a phrase "she wanted the xxxxx", the slot is filled by a noun (or a noun phrase). Syntactically, a noun takes an article ("a", "the") or determiner (something which provides more specification, e.g. "his", "this") before it. For example "this person".

Nouns in English do not all behave regularly, for example not all have a form which can be used grammatically as a plural, e.g. you don't say "*the furniture are over there": these are called uncountable nouns.

Adjectives

Adjectives appear between article (or determiner) and noun. For single syllable adjectives, there is a morphological criterion that they can take comparitive (~er) or superlative (~est) affix; multi-syllable adjectives are not always so regular (e.g. "more random" rather than "randomer", "most random" rather than "randomest"). But comparitive morphemes do not apply to nouns.

Other word classes

Determiners give you grammatical information about nouns, and precede nouns, but you can only get one at a time. E.g. "his table", not "*his the table". They give you information about the object such as ownership (his/her) and position (this, that).

Auxiliaries give you grammatical information about verbs, e.g. tense ("had bought", "will buy"), and modal information ("should buy", "might buy").

Prepositions are words which have no inflections (plural, tense, comparison) so can be morphologically distinguished by saying they have no inflectional possibilities. Semantically, they are used to indicate a relationship between entities, e.g. "he stood behind the door". They can occur after intransitive verbs and before determiners.

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