The main unit of the lexical system of alanguage resulting from the association of a group of sounds with a meaning isa word. This unit is used in grammatical functions characteristic of it. It isthe smallest basic language unit which can stand alone as a complete utterance.The definition of every basic notion is a very hard task; the definition of aword is one of the most difficult items in linguistics because the word hasmany different aspects. It has a sound form with a certain arrangement ofphonemes; it has its morphological structure with a certain types of morphemes;it may occur in different wordforms and various meanings. A word is a semantic,phonological and grammatical unit based on the paradigmatic relations, on theinterdependence of words within the lexical system. The syntagmatic relationsshow the relation of words in the patterns of arrangement. A description of theword based on the results of research and carried out by many scientists ispresented. The problem of creating a word theory based upon the realunderstanding of the relationship between word and thought, on the one hand,and language and society, on the other hand, has been discussed for many years.The efforts of many eminent scholars such as V.V. Vinogradov, A.I. Smirnitsky,O.S. Ahmanova, I.V. Arnold, R.S. Ginzburg deal with the problem of giving aclear exposition of the word as a basic unit of the language. The main pointsmay be summarized as, “The word is one of the fundamental units of language. Itis a dialectical unity of form and content” [Ginzburg, 1985:132].

The word is a speech unit used for thepurposes of human communication, representing a group of sounds, possessing ameaning and characterized by formal and semantic unity. The formal unity of theword can be best illustrated by comparing a word and a wordgroup comprisingidentical constituents. The difference between a blackbird and a black bird isbest explained by their relationship with the grammatical system of thelanguage. The word a blackbird possesses a single grammatical structure. In theword-group a black bird each part can acquire grammatical forms of its own: Theblackest bird, a black night bird.

According to the nature and the number ofmorphemes constituting a word there are different structural types of words inEnglish: simple, derived, compound, compound-derived. Simple words consist ofone root morpheme and an inflexion (in many cases the inflexion is zero), e.g.seldom, chairs, longer, dog, card.

Derived words consist of one root morpheme,one or several affixes and an inflexion, e.g. acceptable, unemployed,disagreeable. Compound words consist of two or more root morphemes and an inflexion, e.g. username, videodisc, book-stores, to baby-sit.

Compound-derived words consist of two ormore root morphemes, one or more affixes and an inflexion, e.g. baby-sitters,middle-of-the-roaders, job-hopper.

When speaking about the structure of wordsstems also should be mentioned. The stem is the part of the word which remainsunchanged throughout the paradigm of the word, e.g. the stem hop can be foundin the words: hop, hops, hopped, hopping. The stem hippie can be found in thewords: hippie, hippies, hippie’s, hippies’. The stem job-hop can be found inthe words: job-hop, job-hops, job-hopped, job-hopping. The most characteristicfeature of word-structure in English is the phonetic identity of the stem withthe word form which habitually represents the word as a whole and with the rootmorpheme. For example, the stem of the verb to talk remains unchangedthroughout its paradigm (talk, talks, talked, talking) and coincides both withone of its word forms – talk and the root morpheme talk-.

 

A word, however, can be divided intosmaller sense units – morphemes. The term “morpheme” is derived from Greekmorphē – (‘form’+ -eme). The Greek suffix –eme has been adopted to denote the smallest unit(cf. phoneme, sememe).

The morpheme is the smallest meaningfullanguage unit. Morphemes occur in speech only asconstituent parts of words but not independently. The morpheme consists of aclass of variants, allomorphs, which are either phonologically ormorphologically conditioned. In the word-cluster please, pleasing, pleasant,pleasure the root morpheme is represented by phonemic shapes [pli:z-] inplease, pleasing and [pleəзə] in pleasure and [plezənt] in pleasant. Insuch cases we say that the phonemic shapes of the word stand in alternationwith each other. These are variants of one morpheme and they are calledallomorphs.

Morphemes are divided into two largegroups:

· lexical or root morphemes;

· grammatical (functional)morphemes. Both lexical and grammatical morphemes can be free and bound.

· Free lexical morphemes areroots of words which express the lexical meaning of the word they coincide withthe stem of simple words, e.g. dog, book, room, house, ball etc.

· Bound lexical morphemes areaffi xes: prefi xes (dis-) disabled,

(un-) unnatural, suffi xes (-ish) girlish, (-ship) friendship and also blocked (unique)root morphemes, e.g. Fri-day, cran-berry.

· Semi-bound (semi-free)morphemes can function both as an affix  and as a free morpheme. For example, themorphemes (well, half) on the one hand, they are free morphemes because theycan exist separately like these: sleep well, half an hour. On the other hand,they are bound in words like well-known, half-done.

· Free grammatical morphemesare function words: articles, conjunctions and prepositions, e.g. (a, an, the,but, and, under, on, in).

· Bound grammatical morphemesare inflexions (endings), e.g. ( -s) teachers for the Plural of nouns, (-ed)added for the Past Indefinite of regular verbs,(-ing) reading for the PresentParticiple, (-er) hotter for the Comparative degree of adjectives. So inflexionscarry only grammatical meaning and they are used for the formation ofwordforms. Having analyzed the lexical units of the English language we can saythat morphemes are arranged according to certain rules, the arrangementdiffering in various types of words and particular groups within the same type.The arrangement of morpheme components underlies the classification of wordsinto different types and enables one to understand how new words appear in thelanguage.