Parts of speech

“Definitions of parts of speech are largely notional and often extremely vague”
INTRODUCTION
Oxford Advanced Learner’s Dictionary defines Parts of Speech as, “One of the classes into which words are divided according to their grammar such as noun, verb, adjective etc”. According to Traditional grammar, “Division of words into different kinds or classes according to their use; the work they do in a sentence is called Parts of Speech”. Most grammar books say that there are eight parts of speech: nouns, verbs, adjectives, adverbs, pronouns, conjunctions, prepositions and interjections.
DEVELOPMENT OF THOUGHT
It is important to be able to recognize and identify the different types of words in English, in order to understand grammar explanations and use the right word -form in the right place. Following is the brief explanation of what the parts of speech are:
Noun
A noun is a naming word. It names a person, place, thing, idea, living creature, quality, or action. Examples: cowboy, theatre, box, thought, tree, kindness, arrival, etc.
Verb
A verb is a word which describes an action (doing something) or a state (being something). Examples: walk, talk, think, believe, live, like, want, etc.
Adjective
An adjective is a word that describes a noun. It tells something about the noun. Examples: big, yellow, thin, amazing, beautiful, quick, important, etc.
Adverb
An adverb is a word which usually describes a verb. It tells how something is done. It may also tell when or where something happened. Examples: slowly, intelligently, well, yesterday, tomorrow, here, everywhere, etc.
Pronoun
A pronoun is used instead of a noun, to avoid repeating the noun. Examples: I, you, he, she, it, we, they, etc.
Conjunction
A conjunction joins two words, phrases or sentences together. Examples: but, so, and, because, or, etc.
Preposition
A word placed before a noun or pronoun to show in what relation the person or thing denoted by it stands in regard to something else. Examples: on, in, by, with, under, through, at, etc.
Interjection
An interjection is an unusual kind of word, because it often stands alone. Interjections are words which express emotion or surprise, and they are usually followed by exclamation marks. Examples: Ouch!, Hello!, Hurray!, Oh no!, Ha!, etc.
This kind of classification goes back to the Greek philosophers Plato and Aristotle, though the first really clearly statement comes from the most famous of Greek grammarians, Dionysius Thrax, who produced a grammar of Greek in about 100 B.C. Dionysius also recognized eight parts of speech. Six of them were identical with those listed above; the only difference in the more modern list is that it has distinguished nouns and adjectives and added the interjections, omitting the participle and article as separate parts of speech. it is never very clear in the grammars why these eight parts of speech must be stressed; they do not appear to be an essential prerequisite for the rest of the grammar, but are introduced rather as an academic exercise. They are there because of the classical tradition and their justification was never challenged. But modern linguists and grammarians like Frank Palmer, C.C.Fries and others have quite serious objections to this traditional classification, as they charge the definitions of these parts of speech are largely notional and extremely vague.
Parts of speech play a crucial role in the formulation of the grammatical rules of languages. It is important to realize, however, that the traditional list of ten or so parts of speech is very heterogeneous in completion and reflects, in many of the details of the definitions that accompany it, specific features of the grammatical structure of Greek and Latin that are far from being universal. Furthermore, the definitions themselves are often logically defective. Some of them are circular; and most of them combine inflectional, syntactic and symmetric criteria which yield conflicting results when they are applied to a wide range of particular instances in several languages. In fact, taken at their face value, the traditional definitions do not work perfectly even for Greek and Latin. Like most of the definitions in traditional grammar, they rely heavily upon the good sense and tolerance of those who apply and interpret them.
It is easy enough to pick holes in the traditional definitions: “A Noun is the name of any person, place or thing”, “A Verb is a word which denotes an action”, “An Adjective modifies a noun”, “A Pronoun stands for a noun”, etc. Nevertheless, most linguists still operate with the terms ‘noun’, ‘verb’, ‘adjective’, etc., and interpret them, explicitly and implicitly, in a traditional way and they are right to do so. It is an important fact about the structure of natural languages that linguists are able to make empirically verifiable statements to the effect that some languages have a syntactic distinction between adjectives and verbs (English, French, Russian, etc.), whereas others (Chinese, Malay, Japanese, etc.) arguably do not; that most languages have a syntactic distinction between nouns and verbs (English, French, Russian, Chinese, Malay, Japanese, Turkish, etc.) but that a few (notably, the American-Indian language Nootka, as described by Sapir) arguably do not; that in some languages adjectives are grammatically more similar to nouns and less similar to verbs than they are in other languages (English, Chinese, Japanese, etc.).
But there is another aspect of the traditional theory of the parts of speech that must be clarified at this point. That the terms ‘noun’, ‘verb’, ‘adjective’ etc., are employed in traditional grammar with the same ambiguity that ‘word’ is; and this ambiguity has been carried over into many otherwise untraditional modern treatments of syntax, which prefer to talk of word-classes, rather than parts of speech. If we decide to restrict the term ‘parts of speech’ to classes of lexemes, saying that boy is a noun, that come is a verb, and so on we can say that boy, boys and boy’s are noun-forms, that come, comes, coming, came are verb-forms and so on.
There is more to this question than simply a desire for terminological consistency. One of the problems with the traditional theory of parts of speech is that, by failing to draw the distinction that has just been drawn, it found itself obliged to recognize that certain words belong simultaneously to two parts of speech. This is most notoriously the case with participles (whose traditional label reflects their dual status). Looked at from one point of view, that of inflectional morphology they are verb-forms; looked at from another point of view, in terms of their syntactic function, they are adjectives (cf. dancing in the dancing girl, construed as “the girls who dance/are dancing”). Similarly, what are traditionally called gerunds (or, more, revealingly verbal nouns) are verb-forms whose syntactic function is characteristically that of nouns (cf. dancing in shoes for dancing and, at one further remove, as a noun used adjectivally in dancing shoes).
A feature of English and some of other languages is that a word can belong to two or more different classes without changing its form. For example, brown is a noun in a nice shade of brown, and adjective in a brown skirt and a verb in please brown the meat. Likewise, straight is a noun in Schumacher accelerated down the straight, an adjective in a straight line, and an adverb in she hit the ball straight. There are many of these, but note that a word can only belong to one part of speech at a time some other languages do not tolerate this, and require each word to belong only to one part of speech.
As a rule the words in a single class do not all show absolutely identical behaviour; instead, they are further divided in to several subclasses, often overlapping, which show somewhat different behaviour. This is subcategorization.
CONCLUSION
The pith and marrow of above said is that the classification of parts of speech into eight classes according to the traditional grammars, is not appropriate. It also indicates that it is impossible to write a grammar of a language without setting up word classes. So the modern linguists, scholars and grammarians are true in their claim that the definitions of these parts of speech are largely notional and extremely vague.