The essential features of phraseological units are: a) lack of semantic motivation; b) lexical and grammatical stability.
As far as semantic motivation is concerned phraseological units are extremely variated from motivated (by simple addition of denotational meaning) like a sight for sore eyes and to know the ropes, to partially motivated (when one of the words is used in a not direct meaning) or to demotivated (completely non-motivated) like tit for tat, red-tape.
Lexical and grammatical stability of phraseological units is displayed in the fact that no substitution of any elements whatever is possible in the following stereotyped (unchangeable) set expressions, which differ in many other respects: all the word and his wife, red tape, calflove, heads or tails, first night, to gild the pill, to hope for the best, busy as a bee, fair and square, stuff and nonsense, time and again, to and for.
In a free phrase the semantic correlative ties are fundamentally different. The information is additive and each element has a much greater semantic independence. Each component may be substituted without affecting the meaning of the other: cut bread, cut cheese, eat bread. Information is additive in the sense that the amount of information we had on receiving the first signal, i.e. having heard or read the word cut, is increased, the listener obtains further details and learns what is cut. The reference of cut is unchanged. Every notional word can form additional syntactic ties with other words outside the expression. In a set expression information furnished by each element is not additive: actually it does not exist before we get the whole. No substitution for either cut or figure can be made without completely ruining the following:
/ had an uneasy fear that he might cut a poor figure beside all these clever Russian officers (Shaw). He was not managing to cutmuch of a figure (Murdoch).
The only substitution admissible for the expression cut a poor figure concerns the adjective.
2. Semantic approach stresses the importance of idiomaticity, functional approach - syntactic inseparability, contextual approach - stability of context combined with idiomaticity.
3. In his classification V.V.Vinogradov developed some points first advanced by the Swiss linguist Charles Bally. The classification is based upon the motivation of the unit, i.e. the relationship existing between the meaning of the whole and the meaning of its component parts. The degree of motivation is correlated with the rigidity, indivisibility and semantic unity of the expression, i.e. with the possibility of changing the form or the order of components, and of substituting the whole by a single word. According to the type of motivation three types of phraseological units are suggested: Phraseological combinations, phraseological unities, and phraseological fusions.
The Phraseological collocations (combinations), are partially motivated, they contain one component used in its direct meaning while the other is used figuratively: meet the demand, meet the necessity, meet the requirements.
Phraseological unities are much more numerous. They are clearly motivated. The emotional quality is based upon the image created by the whole as in to stick (to stand) to one's guns, i.e. 4refuse to change one's statements or opinions in the face of opposition', implying courage and integrity. The example reveals another characteristic of the type, the possibility of synonymic substitution, which can be only very limited, e.g. to know the way the wind is blowing.
Phraseological fusions, completely non-motivated word-groups, (e.g. tit for tat), represent as their name suggests the highest stage of blending together. The meaning of components is completely absorbed by the meaning of the whole, by its expressiveness and emotional properties. Phraseological fusions are specific for every language and do not lend themselves to literal translation into other languages.
REPRODUCIBILITY AND THE PROBLEM OF STABILITY OF PHRASEOLOGICAL UNITS
On stability of Phraseological units. there is a rare unanimity of the vast majority of researchers who consider that stability of phraseological units is shown in their reproducibility in finished form.
The traditional understanding of stability is based on Ferdinand de Saussure's statement though he himself did not use the term 'stability'.
"The most characteristic property of the speech is freedom of a combination; it is necessary to raise, therefore, a question, whether all the syntagmas are equally free. First of all we meet a huge number of the expressions relating certainly to language; these are those quite ready set phrases in which the custom prohibits something to change even in case it is possible, having thought, to distinguish in them significant parts. Approximately the same though to a lesser extent, treats such expressions how 'to booze', 'take aim', 'carelessly' or as thanks to thatů', 'in spite of the fact that...', 'as for... ', etc. Their usual (fixed by language custom) character appears from features of their value or their syntax. Such set expressions cannot be improvised; they are transferred ready by tradition" [Saussure 1993: 122].
Otto Espersen who in the works [Jespersen, 1933: 18] emphasized adheres to the same point of view underlines also that free expressions (variable expressions) each time are created in the speech on a certain sample (pattern), and steady verbal groups at a certain stage of language are not created again, and used in a ready-made form.
The treatment of phraseological units suggested by Ferdinand de Saussure and Otto Espersen, was a big step forward for the time and was the new word in the theory of steady combinations of words.
However it should be noted that the understanding of stability as 'reproducibility in a ready-made form' refers not only to phraseological units, but also to all other units of the language. In the majority of works on phraseology the traditional understanding of stability is considered axiomatic. The similar understanding of stability is incomplete as it fixes only that fact that this verbal group is a language unit whereas for more exact understanding of stability it is not less important to establish as the similar combination of words functions in the speech that quite often brings an essential amendment in understanding of its stability. It is essential, for example, at separation of phraseological units from individual expressions and author's quotes.
The traditional understanding of stability does not reflect specifics of phraseological units of this or that language either in structural, or in the semantic plan and does not give the chance to establish various degrees of stability of verbal groups and to allocate categories, intermediate between phraseological units and variable combinations of words or compound words that, in its turn, complicates the establishment of borders of phraseology in this or that language.
As A.I. Smirnitsky correctly specifies, it is necessary to allocate various cases of reproducibility: reproducibility of verses, formulas, etc., having nature of citing, deliberate repetition, and reproducibility of units of the language, not having nature of citing; these units are applied and reproduced as essentially not having the author, as the general property of the people which is inseparably linked with it [Smirnitsky, 1956: 229]. In view of various nature of reproducibility verses, mathematical formulas, physical laws, etc., not being elements of dictionary structure of language, no matter how often they are repeated, they cannot become phraseological units. It is fully fair and concerning habitual phrases which can be reproduced in a ready-made form.
Phraseological units are steady not because they are reproduced in a ready-made form, and, on the contrary, they are reproduced in a ready-made form because are steady word combinations.
It is true as far as words are concerned. Thus, specifics of stability of phraseological units and words define nature of their reproducibility in a ready-made form. Stability of phraseological units is created in speech, then it is fixed in the language, and then again it is realized in speech.
At reproducibility in a ready-made form both the grammatical model and its lexical filling belong to the language as A.V. Kunin puts it.