Changes in Word Meaning

　　1．Types of changes

　　1）Extension

　　The extension of meaning, the opposite of restriction, means the widening of a word's sense until it covers much more than what it originally conveyed.

　　2）Narrowing

　　Narrowing of meaning, also called restriction of meaning, means that a word of wide meaning acquires a narrower, specialised sense which is applicable to only one of the objects it previously denoted.

　　3）Elevation

　　When the meaning of a word narrows toward a more favourable meaning it is called elevation

　　4）Degradation

　　Degradation means the falling of word meaning into disrepute, for one reason or another. Words once respectable or neutral may shift to a less respectable, or even derogatory meaning.

　　2. Causes of changes

　　1）Extra-linguistic factors

　　（1）historical reason

　　（2）class reason

　　（3）psychological reason

　　2）Linguistic factors

　　（1）shortening

　　（2）borrowing

　　（3）analogy