It has been mentioned that the systems of meanings of polysemantic words evolve gradually. The older a word is, the better developed is its semantic structure. The normal pattern of a word's semantic development is from monosemy to a simple semantic structure encompassing only two or three meanings, with a further movement to an increasingly more complex semantic structure.
In this chapter we shall have a closer look at the complicated processes by which words acquire new meanings.
There are two aspects to this problem, which can be generally described in the following way: a) Why should new meanings appear at all? What circumstances cause and stimulate their development? b) How does it happen? What is the nature of the very process of development of new meanings?
Let us deal with each of these questions in turn.