The semantics of parts of speech
Analysing a language grammatically involves analysing it into a variety of elements and structures: phonemes, morphemes and words, and, within the words, syntactic categories of various sorts. Among these categories are the parts of speech (also known as lexical or grammatical categories): noun, verb, adjective, determiner and so on. We usually think of these classifications as inherent properties of words. We imagine, in other words, that the lexicon of English is arranged with each word specified as belonging to a particular part of speech, or sometimes to several parts of speech. A word’s membership in a particular part of speech category is thus one of its inherent properties. As a result, we say that quickly is an adverb; woman a noun and capsize a verb; on the other hand, catch is both noun and verb (a catch; to catch), and green is noun, verb and adjective (They are on the green; the council is greening the city; I like green asparagus).
Question Find as many English words as possible which can be used as a noun, a verb and an adjective, without any alteration. What semantic changes follow from the change of syntactic category?
Parts of speech are indispensable in stating grammatical generalizations, since they allow us to capture the classes of words to which different morphological and syntactic operations apply. For example, we need the categories noun and verb in order to describe the role of the English nominalizing suffix -er. Given a set of forms think/thinker, glide/glider, race/racer, bind/binder and so on, we can describe the suffix -er as converting a verb into a noun. If those two categories were not part of the grammar, stating the role of -er would be greatly complicated. Similarly, one of the rules for the English noun phrase, NP → (Det) N, makes crucial reference to the categories determiner and noun.
Not all of the categories we use in linguistic analysis can be given semantic definitions. Phonemes like /n/ and /I/ or distinctive features like [± coronal], [± back] are good examples of linguistic units which in themselves just don’t have any meaning. The same is true of phrasal and higher constituents: it makes no sense to ask what the meaning of the category Verb Phrase or Sentence is, since the role of these categories is in the analysis of syntactic arrangement, and they simply lack any independent meaning. Other categories that we use in grammatical analysis, however, do have their own meanings. Individual words are the best example, but other elements, like clause-patterns (declarative, interrogative, imperative), as well as utterances and even whole texts, can also informally be said to have their own meanings: the typical meaning of the interrogative-pattern in English, for instance, is that the clause is a question (see 4.1 for problems and discussion). It also often makes sense to ask for the meaning of elements below the word level, such as some bound morphemes like the English plural marker -s or the tense suffix -ed (see 2.2).
What about the parts of speech? Are they like phonemes or phrasal constituents in simply not having any meaning of their own? Or are they like words and clause-patterns in having an identifiable semantic content? In this section, we will explore just how far it is possible to give a semantic definition of the parts of speech, and what the alternatives to semantic definition might be.
