PARTS OF SPEECH IN ENGLISH
The words of every language fall into classes which are called parts of speech. Each part of speech has characteristics of its own. Parts of speech differ from each other in meaning, form and function.
Different parts of speech have different lexical meanings. For example, verbs are words denoting processes (to work, to live); nouns are names of objects (table, boy); adjectives are words ex- pressing characteristics (good, bad), etc.
Some parts of speech have different grammatical categories, e.g. verbs have the categories of mood, tense, aspect, phase, voice, person and number; nouns have the categories of number and case; adjectives have degrees of comparison, etc.
Other parts of speech are invariable, they have only one form. Here belong such parts of speech as prepositions and conjunctions.
Parts of speech also differ from each other in their syntactic functions. For example, verbs have the function of the predicate in the sentence, nouns are often used as the subject or the object of the sentence, adjectives serve as attributes or predicatives; adverbs are generally adverbial modifiers, etc.
These characteristic features will be described in detail when each part of speech is considered individually. In addition, all words may be divided into two main groups: notional and structural.
Notional words have distinct lexical meanings and perform independent syntactic functions in the sentence: they serve either as primary or secondary parts of the sentence. To this group belong the following parts of speech: verbs, nouns, adjectives, numerals, pronouns and adverbs.
Structural words differ from notional words semantically: their lexical meaning is of a more general character than that of notional words (e.g. in, and, even). Moreover, they are sometimes altogether devoid of it (e.g. the articles the and a, the conjunction that, the preposition of, etc.). Structural words do not perform any independent syntactic function in the sentence but serve either to express various relations between words in a sentence (e.g. the trees in the garden, Tom and Joe, etc.) or to specify the meaning of a word (e.g. the book, a book, etc.). The following parts of speech are to be treated as structural words: articles, prepositions and conjunctions.
The division of words into notional and structural is connected with certain difficulties. For example, verbs, which, on the whole, are to be treated as notional words, include certain words which serve as structural elements (e.g. modal verbs), some other verbs may function either as notional words or as structural words (e.g. to look is a notional verb in He looked at me and a structural word — a link-verb — in He looked tired; the verb to have is a notional verb in I have a car and a structural word — a modal verb — in I had to do it). Pronouns may be quoted as another example since, on the one hand, they have, like all notional words, independent syntactic functions in the sentence but, on the other hand, they are devoid of distinct lexical meaning