Introduction. It has been repeatedly pointed out that word-groups viewed as functionally and semantically inseparable units are traditionally regarded as the subject matter of phraseology. It should be noted, however, that no proper scientific investigation of English phraseology has been attempted until quite recently. English and American linguists as a rule confine themselves to collecting various words, word- groups and sentences presenting some interest either from the point of view of origin, style, usage, or some other feature peculiar to them. These units are habitually described as idioms but no attempt has been made to investigate these idioms as a separate class of linguistic units or a specific class of word-groups.

Enriching the vocabulary of a language by phraseological units

The vocabulary of a language is enriched not only by words but also by phraseological units. Phraseological units are word-groups that cannot be' made in the process of speech, they exist in the language as ready-made units. They are compiled in special dictionaries. The same as words phraseological units express a single notion and are used in a sentence as one part of it. American and British lexicographers call such units «idioms». We can mention such dictionaries as: L. Smith «Words and Idioms», V. Collins «А Book of English Idioms» etc. In these dictionaries we can find words, peculiar in their semantics (idiomatic), side by side with word-groups and sentences. In these dictionaries they are arranged, as a rule, into different semantic groups. Phraseological units can be classified according to the ways they are formed, according to the degree of the motivation of their meaning, according to their structure and according to their part-of-speech meaning. A.V. Koonin classified phraseological units according to the way they are formed. He pointed out primary and secondary ways of forming phraseological units. Primary ways of forming phraseological units are those when a unit is formed on the basis of a free word-group:         

1. a) The most productive in Modern English is the formation of phraseological units by means of transferring the meaning of terminological word-groups:

E.g. in cosmic technique we ran point out the following phrases:

«launching pad» in its terminological meaning is «стартовая площадка»,in its transferred meaning -«отправной пункт», «to link up» - «стыковка космических кораблей, соединение», in its tranformed meaning it means - «знакомиться»;

A large group of phraseological units was formed from free word groups by transforming their meaning.

E.g. «granny farm» - «пансионат для старых людей»,

 «Trojan horse» - компьютерная программа предварительно составленная для повреждения компьютера»

Formation of phraseological units.

Phraseological units can be formed by means of alliteration.

E.g. «a sad sack» - «несчастный случай», «culture vulture» - « человек интересующийся искусством», «fudge and nudge» - «уклончивость».

They can be formed by means of expressiveness; especially it is characteristic for forming interjections.  E.g. «My aunt! », « Hear, hear!» etc.

They can be formed by means of distorting a word group, e.g. «odds and ends» was formed from «odd ends», they can be formed by using archaisms.

E.g. «in brown study» means «in gloomy meditation» where both components preserve their archaic meanings, they can be formed by using a sentence in a different sphere of life.

E.g. «that cock won't fight» can be used as a free word-group when it is used in sports (cock fighting), it becomes a phraseological unit when it is used in everyday life, because it is used metaphorically, they can be formed when we use some unreal image.

E.g. «to have butterflies in the stomach» - «испытывать волнение», «to have green fingers - «преуспевать, как садовод-любитель».

They can be formed by using expressions of writers or politicians in everyday life, e.g. «corridors of power»(Snow), «American dream» (Alby) «locust years» (Churchill), «the winds of change» (McMillan).

Secondary ways of forming phraseological units are those when a phraseological unit is formed on the basis of another phraseological unit; they are:

1. a) Conversion or forming verb forms from nominal constructions or vice versa.

 E.g. «to vote with one's feet» was converted into «vote with one's feet»;

• Changing the grammar form into a whole sentence. E.g. «Make hay while the sun shines» is transferred into a verbal phrase - «to make hay while the sun shines»;
• Analogy or taking appropriate word for the situation, g. «Curiosity killed the cat» was transferred into «Care killed the cat»;
• Contrast, g. «cold surgery» - «a planned before operation» was formed by contrasting it with «acute surgery», «.thin cat» - «a poor person» was formed by contrasting it with «fat cat»;
• Shortening of proverbs or sayings g. from the proverb «You can't make a silk purse out of a sow's ear» by means of clipping the middle of it the phraseological unit «to make a sow's ear» was formed with the meaning «помилятись».
• borrowing phraseological units from other languages, either as translation loans, g. « living space» (German), « to take the bull by the horns» (Latin) or by means of phonetic borrowings «meche blanche» (French), «corpse d'elite» (French), «sotto voce» (Italian) etc.

Phonetic borrowings among phraseological units refer to the bookish style and are not used very often. There are different combinations of words. Some of them are free, e.g. to read books (newspapers, a letter, etc.) others are fixed, limited in their combinative power, e.g. to go to bed, to make a report. The combinations of words which are fixed (set-expressions) are called phraseological units.

A free combination is a syntactical unit, which consists notional and form words, and in which notional words have the function of, independent parts of the sentence. In phraseological unit words are not independent. They form set-expressions, in which neither words nor the order of words can be changed. Free combinations are created by the speaker. Phraseological units are used by the speaker in a ready form, without any changes. The whole phraseological unit has a meaning which may be quite different from the meaning of its components, and therefore the whole unit, and not separate words, has the function of a part of the sentence.

Phraseological units consist of separate words and therefore they are different words, even from compounds. Word has several structural forms, but in phraseological units only one of the components has all the forms of the paradigm of the part of speech it belongs to e.g. to go to bed, goes to bed, went to bed, gone to bed, going to bed, etc., the rest of the components do not change their form.

By the classification of Academician V. Vinogradov phraseological units are devided into three groups: phraseological combinations, phraseological units and phraseological fusions.

Phraseological combinations are often called traditional because words are combined in their original meaning but their combinations are different in different languages, e.g. cash and carry - (self-service shop), in a big way (in great degree) etc. It is usually impossible to account logically for the combination of particular words. It can be explained only on the basis of tradition, e.g. to deliver a lection (but not to read a lecture). In phraseological combinations words retain their full semantic independence although they are limited in their combinative power, e.g. to wage wax (but not to lead war), to render assistance, to render services (but not to render pleasure).

Phraseological Unities: In phraseological unities the meaning of the whole can be guessed from the meanings of its components, but it is transferred (metaphorical or metonymical)

 E.g. to play the first fiddle (to be a leader in something), old salt (experienced sailor) etc. The meaning of the whole word combination is not the sum of the meanings of its components, but it is based on them and the meaning of the whole can be inferred from the image that underlies the whole expression, e.g. to get on one's nerves, to cut somebody short, to show one's teeth, to be at daggers drawn. Phraseological unities are equivalents of words as:

1) only one of components of a phraseological unity has structural forms' e.g. to play (played, is playing, etc.) the first fiddle (but not played the first fiddles); to turn ( turned, will turn, etc.) a new leaf ( but not to turn newer leaf or new leaves); 2) the whole unity and not its components are parts of the sentence in syntactical analysis, e.g. in the sentence He took the bull by the horns (attacked a problem boldly) there are only two parts: he - the subject, and took the bull by the horns - the predicate.

Phraseological Fusions: In phraseological fusions the degree of motivation is very low, we cannot guess the meaning of the whole from the meanings of its components, they are highly idiomatic and cannot be translated word for word into other languages.

1. g. to pull one's leg (to deceive); at sixes and sevens (in confusion); a mare's nest ( a discovery which turns out to be false or worthless); to show the white feather (to show cowardice); to ride the high horse (to put on airs).

 Phraseological fusions are the most idiomatic of all the kinds of phraseological units. Phraseological fusions are equivalents of words: fusions as well as unities form a syntactical whole in analysis.

Conclusion

In conclusion we can say that translators have a lot of different things to consider before diving into to translating a text. The discrepancies in grammar and vocabulary between languages make it difficult to literally translate every text word for word. In order to account for this, translators use a wide variety of translation techniques in order to accurately translate any given text. If you have ever tried to use a free online translation service and received a translation that didn’t make much sense, you’ve realized how difficult it can be to translate from one language to another. Professional translations are completed by trained professionals who know the tricks of the trade.

To conclude, translation must take into consideration the linguistic, semantic and pragmatic context. Most translation theorists insist on the need to consider all the relevant situational contexts and the relevant social and cultural contexts. Translation always involves cultural translation, because cultures not only express  ideas differently, but also they shape concepts and texts differently.