Alongside with separate words speakers use larger blocks consisting of more than one word yet functioning as one word. These set expressions are extremely variegated structurally, functionally, semantically and stylistically. Some word groups (e.g. at last, point of view, by means of, take place) seem to be functionally and semantically inseparable. Such word-groups are usually described as set phrases and they are studied by the branch of lexicology which is called phraseology.
The component members in other word-groups (e.g. a week ago, men of wisdom, take lessons, kind of people) seem to possess greater semantic and structural independence.
Word-groups of this type are defined as free word-groups or phrases. Words are used in certain lexical context, i.e. in combination with other words. E.g. the noun question is often combined with such adjectives as vital, pressing, urgent, disputable, delicate etc.
The aptness of a word to appear in various combinations is described as its lexical valency or collocability.
The lexical valency of correlated words in different languages is not identical.
e.g. English Russian
garden flowers
but
pot-flowers
Word-groups like separate words may also be analyzed from the point of view of their motivation.
Word-groups are lexically motivated if the combined lexical meaning of the group is clear from the meaning of their components.
e.g. heavy weight, to take lessons are motivated while structurally identical word-groups red-tape (), to take place are lexically
non-motivated.
In these groups the constituents do not possess at least synchronically the denotational meaning found in the same words outside these groups (to be more exact do not possess any individual lexical meaning of their own).
The degree of motivation can be different (complete motivation, lack of motivation, intermediate cases).
e.g old man and old boy both are motivated lexically and structurally. But the degree of motivation is higher in old man
Seemingly identical word-groups are found to be motivated or non-motivated depending on their semantic interpretation.
e.g. apple sauce is motivated in the meaning but non-motivated in the meaning nonsense.
It follows that word-groups may also be classified into motivated and non-motivated units. Non-motivated word-groups are habitually described as phraseological units or idioms.
Phraseological units are contrasted to free phrases. A free phrase permits substitution of any of its elements without semantic change in the other element or elements.
If no substitution is possible it is a phraseological unit.
e.g. phraseological units:
all the world and his wife ,
the man in the street
red tape
calf love
busy as a bee
stuff and nonsense
time and again
tit for tat
to and fro -
free phrases:
to cut a poor figure we can substitute poor by ridiculous, grand).
In speech set phrases are usually used as one member of the sentence:
He took to his heels. Here we have only 2 members.
