What are idioms - статья на английском языке

DIFFERENT ASPECTS OF THE IDIOM
We shall now take a close look at some aspects of idioms. An important fact which must be stressed is that idioms are not only colloquial expressions, as many people believe. They can appear in formal style and in slang. They can appear in poetry or in the language of Shakespeare and the Bible. What, then, is an idiom? We can say that an idiom is a number of words which, taken together, mean something different from the individual words of the idiom when they stand alone. The way in which the words are put together is often odd, illogical or even grammatically incorrect. These are the special features of some idioms. Other idioms are completely regular and logical in their grammar and vocabulary. Because of the special features of some idioms, we have to learn the idiom as a whole and we often cannot change any part of it (except perhaps, only the tense of the verb). English is very rich in idiomatic expressions. In fact, it is difficult to speak or write English without using idioms. An English native speaker is very often not aware that he is using an idiom; perhaps he does not even realize that an idiom which he uses is grammatically incorrect. A non-native learner makes the correct use of idiomatic English one of his main aims, and the fact that some idioms are illogical or grammatically incorrect causes him difficulty. Only careful study and exact learning will help.
It cannot be explained why a particular idiom has developed an unusual arrangement or choice of words. The idiom has been fixed by long usage — as is sometimes seen from the vocabulary. The idiom to buy a pig in a poke means 'to buy something which one has not inspected previously and which is worth less than one paid for it'. The word poke is an old word meaning sack. Poke only appears in present day English with this meaning in this idiom. Therefore, it is clear that the idiom has continued to be used long after the individual word.
There are many different sources of idioms. As will be made clear later, the most important thing about idioms is their meaning. <...> Many idiomatic phrases come from the every-day life of Englishmen, from home life, e. g. to be born with a silver spoon in one's mouth, to make a clean sweep of something, to hit the nail on the head. There are many which have to do with food and cooking, e.g. to eat humble pie, out of the frying-pan into the fire, to be in the soup. <...>
Idioms take many different forms or structures. They can be very short or rather long. A large number of idioms consist of some combination of noun and adjective, e.g. cold war, a dark horse, French leave, forty winks, a snake in the grass. Some idioms are much longer: to fish in troubled waters, to take the bull by the horns, to cut one's coat according to one's cloth.
When and where to use idioms
<...>One of the main difficulties is that the learner does not know in which situations it is correct to use an idiom. He does not know the level of style, that is, whether an idiom can be used in a formal or in an informal situation. Help is given in this book with the markings formal and informal. Unmarked idioms can be used in any situation. <...>
The expressions marked formal are found written more than in spoken English and are used to show a distant relationship between the speakers. Such expressions would be used for example when making a formal speech to a large audience. Expressions marked informal are used in every-day spoken English and in personal letters. (Slang expressions are used in very informal situations between good friends. Learners should not make frequent use of slang expressions as they usually — but unexpectedly — become out-of-date and sound strange.) It is advisable to concentrate on the expressions which are marked informal and on the unmarked expressions which are neutral in style and can be used in any situation.
(From "English Idioms and How to Use Them" by Jennifer Seidl/W.McMordie)