Notes on lexical categories

• Lexical categories
• Describing, depicting, pointing

I've divided the list up into closed-class and open-class categories. As Johnston and Schembri mention, closed-class categories contain a relatively small number of items; by definition, they are listable and not ordinarily open to new members. By contrast, open-class categories easily welcome new members, whether by borrowing, compounding, neologism, or other means. The status of interjections is somewhat murky; on the whole, they probably belong with closed-class items, as in (1). For the remainder of the discussion, I'll omit them, as they are not a major category.

Johnston and Schembri's list extends straightforwardly to ASL, and in fact it corresponds closely to what traditional school grammar would propose for spoken languages. For instance, the list corresponds almost exactly to the lexical classes used in the Oxford English Dictionary (OED).¹

What is the basis for distinguishing among the various lexical categories? Fundamentally, any word or sign in human language has two components:

• a function (or meaning), and
• a form.

For this reason, lexical categories can be distinguished on the basis of meaning-based (semantic) or form-based (morphosyntactic) considerations, or both. Semantic considerations concern the conceptual underpinning of a word class. They are largely independent of language and even modality, and they are the ones ordinarily invoked by traditional school grammar in adages like "A noun is the name of a person, place, or thing." Morphosyntactic considerations concern the way that the various words or signs combine with each other, and in particular how they combine with inflectional morphemes. For instance, in English, verbs inflect for tense (present play, past played, future will play) and aspect (punctual played, progressive were playing), whereas nouns don't. Conversely, in many languages, nouns (and other categories) inflect for case and gender, whereas verbs don't. (English preserves vestiges of case inflection in the distinction between subject pronoun forms like I or we vs. object pronoun forms like me or us.)

Some languages have hardly any morphology. Chinese is a well-known case of this type. In such languages, lexical classes can still be distinguished, but only (or at least mostly) on the basis of semantic considerations. Conversely, it is not easy to come up with shared semantic criteria for some lexical classes (especially closed-class categories). For instance, it is clear that English prepositions like in, over, under, and so on refer to spatial relations. But it is not clear at all what semantic feature they share with other prepositions like of or despite. Instead, what makes English prepositions (and closed-class items more generally) a lexical class is their formal ability to combine with other forms. In particular, the members of the closed class of English prepositions combines with noun phrases to form prepositional phrases. Noun phrases in turn consist of nouns and (optional) determiners; the closed-class determiners (a(n), the, this, that, some, and so on) are defined by their formal ability to combine with open-class nouns (which are defined both formally and semantically).

Table 1 gives the lexical categories in (1), with some of the cells for "Semantic basis" filled in, and all of the cells for "Morphosyntactic basis" filled in for English. How might you fill in the missing information?

Table 1: Evidence for distinguishing lexical classes
Lexical class	Semantic basis	Morphosyntactic basis
	English	ASL
Noun	Describes classes of objects, concepts, phenomena	Inflects for number (at least for pluralizable nouns)	?
Verb	Describes states, activities, events	Inflects for person/number (3rd person singular present), tense, aspect	?	Inflects for comparative (-er/more) and superlative (-est/most) (at least for gradable adjectives). Restricted to modifying nouns.	?
Adverb	?	-ly (in many cases); restricted to modifying any category except nouns	?
Determiner	?	Some inflection for number (as in this vs. these). Combines with nouns.	?
Pronoun	Picks out individual discourse referent(s)	Inflects for number, case (but unlike many other spoken languages, not gender in the linguistic sense)	?
Auxiliary verb	Modifies verbs with respect to time, modality, evidentiality (first-hand vs. second-hand evidence), and the like	Does not inflect like ordinary verbs, but combines with them	?
Preposition	No common semantic basis	Combines with noun phrases, prepositional phrases, adverb phrases	?
Subordinating conjunction	?	Combines with sentences	?
Coordinating conjunction	Expresses Boolean operators AND, OR	Links two phrases or sentences	?

Table 1: Evidence for distinguishing lexical classes
Lexical class	Semantic basis	Morphosyntactic basis
	English	ASL
noun	describes classes of objects, concepts, phenomena	inflection for number (at least for pluralizable nouns)	?
verb	describes states, activities, events	inflection for person/number (3rd person singular present), tense, aspect	?
adjective	?	inflection for comparative (-er/more) and superlative (-est/most) (at least for gradable adjectives); restricted to modifying nouns	?
adverb	?	-ly (in many cases); restricted to modifying any category except nouns	?
determiner	?	some inflection for number (as in this vs. these); combines with nouns	?
pronoun	picks out individual discourse referent(s)	inflection for number, case (but unlike many other spoken languages, not gender in the linguistic sense)	?
auxiliary verb	modifies verb with respect to time, modality, evidentiality (first-hand vs. second-hand evidence), and the like	does not inflect like ordinary verbs, but combines with them	?
preposition	no common semantic basis	combines with noun phrases, prepositional phrases, adverb phrases	?
subordinating conjunction	?	combines with sentences	?
coordinating conjunction	expresses Boolean operators AND, OR	links two phrases or sentences	?

Describing, depicting, pointing