Analyse the functions of, word classes.

In English grammar, a word class is a set of words that display the same formal properties, especially their inflections and distribution. The term "word class" is similar to the more traditional term, part of speech. It is also differently called grammatical category, lexical category, and syntactic category. The two major families of word classes are lexical (or open or form) classes (nouns, verbs, adjectives, adverbs) and function (or closed or structure) classes (determiners, particles, prepositions, and others). The distinction between lexical and grammatical meaning determines the first division in our classification: form-class words and structure-class words. In general, the form classes provide the primary lexical content; the structure classes explain the grammatical or structural relationship. Think of the form-class words as the bricks of the language and the structure words as the mortar that holds them together.