Inflectional Morphology: Nouns, Verbs, and Adjectives

Inflectional morphology concerns functional morphemes, which usually carry logical meanings and attach to lexical items, that is, to nouns, verbs, and adjectives (with adverbs treated under adjectives). A recurring theme is that the lexical categories are best defined by their grammatical properties rather than their semantic ones. The most comprehensive treatment of what makes a category a noun, verb, or adjective is Mark Baker's Lexical Categories (2003), on which much of the following is based in simplified form.

Nouns

The word noun is hard to define. School definitions such as "a person, place, thing, or idea" do not work, since a noun can also be an event, as in "the examination lasted five hours." Within linguistics nouns are therefore defined mainly by syntax. Baker, for instance, holds that nouns have a referential index; here a noun is defined as a word that can be the complement of determiners, quantifiers, or numerals, and can stand in the argument position of a verb.

The sentence has the plural nouns articles and oxen. How a morpheme is manifested does not affect its interpretation: the plural is -s on articles and -en on ox, but both are simply plural. Some nouns resist pluralization, the classic case being mass nouns such as waters, which do not combine well with plural morphemes, in contrast to count nouns; the semantics of a noun can be incompatible with certain functional elements. Determiners, quantifiers, and numerals help fix a noun's interpretation. Greek ho Iēsous is ordinary, but a literal English "the Jesus" is not, because English proper nouns do not combine well with the definite article. Since the form is grammatical in one language and not the other, either the article differs between the two languages or proper nouns do; the more likely view is that the Greek article differs, and asking how it differs illuminates what the article means elsewhere.

Verbs

A verb is defined as a word that has a subject and can be inflected for tense. In the sentence, hugged is a verb with the subject "the dermatologist," and was is also a verb.

Having a subject is, for Baker, the defining characteristic of verbs, and its semantic corollary is that verbs are predicates: words needing other elements to complete them. The bare word hug leaves an incomplete thought until a subject and object are supplied, as in the dermatologist hugged a pretty girl. Verbs are also inflected for tense specifically, rather than aspect or mood, since tense appears special; a Greek participle, for example, is inflected for aspect but not tense and is arguably not a verb, while English hugged and was are both past tense.

Every verb has an argument structure that can shape its interpretation. Verbs differ in the arguments they require: hug requires the person hugged to be its direct object, whereas play allows a direct object only as the thing played, so played a board game works but played a pretty girl does not mean playing with her. Interpretation also interacts with tense and aspect and with other clause elements. The dermatologist hugged a pretty girl reads as a one-time event, but played with a pretty girl ... when they were younger reads as habitual, the adverbial clause driving the habitual reading with play though not readily with hug. Analyzing a verb thus requires knowing both the verb's meaning and how it combines with such morphology.

Adjectives

An adjective is defined as a word that modifies a noun and can combine with degree morphemes. The sentence has pretty and latest. Adverbs are set aside: it is debated whether they form a real category, and Baker treats them as adjectives, noting that some languages lack adverbs entirely. In English, nouns can also modify nouns, as journal modifies article in journal articles, but degree morphology such as the superlative -est (prettiest, latest) or the comparative (prettier, later) normally combines with adjectives.

Adjectives can modify nouns in different ways. Pretty girl carries the entailments that the individual is both pretty and a girl, but beautiful dancer is ambiguous: either the individual is a dancer and is beautiful, or she dances beautifully without necessarily being beautiful herself. The available readings depend on the particular adjective and noun.

Degree morphology and scale structure also shape interpretation. Adjectives convey different kinds of properties, and their scale structure helps reveal which. Most adjectives have scale structure, but some do not: wooden resists comparison, since "more wooden" usually just means containing more wood. Scale structure further correlates with permanence: pretty is treated as a constant property of an individual, whereas hungry is transient, describing a current state rather than a stable trait. Such contrasts, tied to how adjectives combine with degree words and to their scale structures, allow adjectives to be sorted into classes and correctly interpreted.