4. The lexico-grammatical classes of words. Parts of speech and criteria for their classification.

The term “parts of speech” is accepted by modern linguistics to denote the lexico-grammatical classes of words correlating with each other in the general system of language on the basis of their grammatically relevant properties (semantic, formal and functional properties).

The traditional criteria for the classification of parts of speech are meaning, form and function of words. The semantic criterion refers to the generalized semantic properties common to the whole class of words, e.g.: the generalized (or, categorial) meaning of nouns is “thingness”, of verbs process, of adjectives substantive property, of adverbs non-substantive property. The formal criterion embraces the formal features (word-building and word-changing) that are characteristic for a particular part of speech, e.g.: the noun is characterized by a specific set of word-building affixes, cf.: property, bitterness, worker, etc., and is changed according to the categories of number, case and article determination: boy-boys, boy – boy’s, boy – the boy – a boy, etc. Combinability is also a relevant formal feature for each particular part of speech; for example, verbs can be modified by adverbs, while nouns cannot (except in specific contexts). The functional criterion is based on the functions that the words of a particular class fulfill in the sentence, e.g.: the most characteristic functions of the noun are those of a subject and an object; the only function of the finite form of the verb is that of a predicate; the adjective functions in most contexts as an attribute; the adverb as an adverbial modifier.

Traditionally, all parts of speech are subdivided on the upper level of classification into notional words and functional words. Notional words, which traditionally include nouns, verbs, adjectives, adverbs, pronouns and numerals, have complete nominative meanings, are in most cases changeable and fulfill self-dependent syntactic functions in the sentence. Functional words, which include conjunctions, prepositions, articles, interjections, particles, and modal words, have incomplete nominative value, are unchangeable and fulfill mediatory (посреднеческий), constructional syntactic functions.

Henry Sweet divided all the words in English into “declinables” and “indeclinables”. The syntactic approach, which establishes the word classes in accord with their functional characteristics, is more universal. Ch. Fries selected the most widely used grammatical constructions and used them as substitution frames: the frames were parsed (разобраны) into parts, each of them got a separate number, and then Ch. Fries conducted a series of substitution tests to find out what words can be used in each of the positions. Some of the frames were as follows: The concert was good (always). The clerk remembered the tax (suddenly). The team went there. All the words that can be used in place of the article made one group, the ones that could be used instead of the word “clerk” another, etc. The results of his experiments were surprisingly similar to the traditional classification of parts of speech: four main positions were distinguished in the sentences; the words which can be used in these positions without affecting the meaning of the structures were united in four big classes of words, and generally speaking coincide with the four major notional parts of speech in the traditional classification: nouns, verbs, adjectives and adverbs. Besides these “positional words” (“form-words”), Ch. Fries distinguished 15 limited groups of words, which cannot fill in the positions in the frames. These “function words” are practically the same as the functional words in the traditional classification.