The things and the situations that language is about and the utterance contexts in which language occurs can be seen in terms of a small set of very general, abstract properties. For example, things are either objects or masses or they are abstractions which can be seen as more like objects or more like masses. Situations have a time when they were, are, or will be true. And utterance contexts involve various kinds of possible social relationships between the hearer and the speaker. Each language directly represents some of these abstract properties using words such as the, some, and was or meaningful parts of words, called morphemes, such as -s, -ed, and -ing. Each such form represents a grammatical category, a way of grouping things or situations or contexts on the basis of one of the abstract properties. These forms behave in a different way from the nouns, verbs, and adjectives we have looked at in previous chapters.
First, languages differ a lot in which grammatical categories they make use of. A natural translation of the English sentence I saw a movie into Japanese, eiga o mimashita, has no part that corresponds to either the English word I or the English word a. But the Japanese sentence does have a morpheme that tells the role of the movie in the seeing and a morpheme that conveys something about the social distance between the Speaker and Hearer. Neither of these is present in the English sentence. Second, grammatical categories are in a sense forced on the speakers of a language. In English, we need the -s on pencils in the phrase three pencils whether we like it or not; three pencil is ungrammatical even though it is perfectly understandable. Third, the linguistic forms that convey grammatical categories tend to look different than nouns, verbs, and adjectives. For example, some, such as the -s in pencils, can not even be pronounced in isolation. In this chapter we'll look at how grammatical categories "slice up" the world by dividing it into a set of very abstract semantic categories; what form they take in language; and how they vary across languages. In the process we'll be looking inside words again, this time not at phonological units but at the meaningful units that make up many words, for example, the pencil and -s in pencils.