Chapter 7 Changes in Word Meaning词义的演变
Vocabulary is the most unstable element of a language as it is undergoing constant changes both in form and content. Comparatively the content is even more unstable than the form.
Types of Changes 词义变化的种类（extension,narrowing,degradation,elevation and transfer）
Extension or generalization词义的扩大:is the name given to the widening of meaning which some words undergo.[companion (old)one who shares bread (ex)a company]
Narrowing or specialization词义的缩小：is the opposite of widening meaning. When a common words is turned into a proper noun, the meaning is narrowed. [meat (old)food (na)flesh of animals]
Elevation or amelioration of meaning词义的升华: the process by which words rise from humble（粗陋的） beginnings to positions of importance. [knight (old)servant (el)rank below baronet从男爵]
Degeneration or pejoration词义的贬降:A process whereby words of good origin fall into ill reputation or no-affective words come to used in derogatory sense.[silly (old)happy (de)foolish]
Transfer词义的转移:Words which were used to designate指明 one thing but later changed to mean something else have experienced the process of semantic transfer.（140）
Causes of Semantic Change词义变化的原因
Extra-linguistic factors 141
1 Historical reason 2 Class reason (elevation or degradation) 3 Psychological reason
Linguistic factors：the change of meaning may be caused by internal factors with in the language system.
