Category features

So far we have discussed two kinds of category:

Lexical categories:

These are the parts of speech (POS), i.e. Noun, Pronoun, Determiner, Adjective, Verb, Adverb, Conjunction, Preposition, Interjection.

Phrasal categories:

These are complex categories such as NP, PP, VP, consisting of one or more lexical or phrasal categories.

The typical form of grammar rule used in English defines syntagmatic and paradigmatic relations between these categories, and have the following properties:

Left hand side (LHS):

On the left-hand side of the rule there is only one symbol, which is always a phrasal category (known more formally as a non-terminal symbol.

Right hand side (RHS):

On the right hand side of the rule there is at least one symbol, maybe more, each of which may be either a non-terminal symbol or a terminal symbol, each of which represents a syntagmatic part of the unit represented by the larger symbol.

Non-terminal symbols:

Corresponds to a complex, phrasal category.

Terminal symbols:

Corresponds to a basic unit of grammar, such as a word in a sentence.

Pre-terminal symbols:

Corresponds to a POS, i.e. it stands for a whole set of paradigmatically related terminal symbols.

Syntagmatic relations:

The relation between items on the LHS of a rule is a syntagmatic relation, the part-part relation. The relation between the LHS and the RHS is also a syntagmatic relation: the part-whole relation.

Paradigmatic relations:

The relation between alternative RHS for the same LHS is a paradigmatic relation of similarity - these alternative items (such as N alone, or Det N, or Adj N, or Det Adj N for NP) show paradigmatic relations between structurally similar but still rather different NPs. The relation between pre-terminal symbols and the various terminal symbols of the same category is also a paradigmatic relation - the, this, that, those, ... are grammatically similar and belong to the category of determiners, represented by the pre-terminal symbol Det.

Paradigmatic relations between different lexical and phrasal categories can also be identified. For instance, Adjectives have a nominal grammatical quality in that they occur in NPs and modify Ns. On the other hand they also have a verbal grammatical quality, in that they occur predicatively in VPs with copula verbs).

Nouns, however, do not behave grammatically like verbs (although semantically - but here we are discussing grammar, not meaning - they may refer to events etc. just like verbs).

And verbs do not behave grammatically like nouns.

And prepositions, which differ from other grammatical words, are neither very ``nouny'' nor very ``verby''.

There is much more that can be said on this topic...