The word is the basic unit of language. The principle characteristics of the word are as follows:
1) The word is a unity of the external and the internal structure, i.e. a unity of form and content; thus, it is a two-facet unit.
By the external structure of the word we mean its sound form, morphemic composition, and derivational structure.
The internal (or semantic) structure of the word is all its meanings together.
2) The word is characterized both by external (formal) unity and internal unity.
Its external unity means that a word possesses a single grammatical framing,
e.g. blackbird – blackbirds (pl). The first component black can't have any grammatical forms of its own, whereas in a word-group each constituent can have its own grammatical forms, e.g. the blackest birds I've ever seen.
In a word-group, other constituents can be inserted between its components,
e.g. a black night bird, which is impossible so far as the word is concerned. Its component morphemes are permanently linked together, unlike word-groups, whose components possess a certain amount of structural freedom.
Semantic (internal) unity means that each meaningful word conveys one concept,
e.g. in the word-group a green house each word conveys its own concept: green "coloured like grass", house "a building". The word greenhouse conveys only one concept "a building of glass for rearing delicate plants".
3) The word is a cluster of forms and variants:
a) phonetic variants, e.g. schedule ['skedju:l], again [ə'geın] ;ʒʒə
b) morphological variants, e.g. dreamed/dreamt, dived/dove (AmE);
c) parallel formations of the type geographic/geographical;
(but compare historic - historical, which are separate words);
d) lexico-semantic variants, by which we mean one polysemantic word in its different meanings,
e.g. bird 1) a feathered living creature
2) (sl) young woman
3) (coll) person.
In speech, a certain variant of a word is used in every speech act, but all its variants are identified by language users as making up one and the same word.
4) The word is capable of grammatical employment. In speech, it is used in one of its grammatical forms, which are the smallest units at syntactic level, in a certain function.
The word is a nominative language unit, an association of a particular meaning with a particular series of sounds, capable of grammatical employment.
1.5. There are several approaches to the study of the word.
1) Some decades ago lexicology was characterized by an atomistic approach, which is now obsolete, i.e. lexical units were studied as unconnected separate items.
2) The vocabulary is studied as a system (systemic approach), i.e. the word is studied in its relations to other words in the vocabulary as a component of various sets, groups, fields.
e.g. the word high is studied through its relations to other words: high - tall (synonymy), high - low (antonymy), high - highly, highness (derivational cluster), etc.
(3) The word is studied through its relation to its referent as a nominative unit (nominative approach). The nominative approach is concerned with how things get their names.
e.g. The escalator began life as the "Reno Inclined Elevator", named after its inventor, Jesse Reno, who installed the first one in 1896. "Escalator" was the trade name used by the Otis Elevator Company when it joined the market with a version of its own four years later, but for years afterwards most people called it "a movable stairway".
4) The functional approach studies how words are combined in speech, i.e. a word is observed, studied and described in its typical contexts,
e.g. the notion "group of the same kind of living things" is expressed by the words herd, flock, flight, shoal, school, pack, troop, colony, but flock is used only with sheep, goats, or birds.
5) The communicative approach studies how words are used for purposes of communication, e.g. it studies pragmatic conventions about language use (social and cultural), speech etiquette, i.e. the appropriate use of language unites in various situations.
e.g. OK is one of the most important discourse markers in English.
a) It indicates you accept an offer, suggestion, request.
b) It serves as a bridge between two topics or stages of a talk.
c) It shows the talk is drawing to a close, etc.
