Abstract: Language is always in a state of constant change. The present book, viewing from aspects like so-ciety, psychology, physiological and linguistic structures, discusses the motivations that cause changes in pronunciation, words, grammar and attempts to answer the question why language necessarily changes.#@#@#摘要: 语言总是处在不断的变化之中。本书从社会、心理、生理和语言结构等方面探讨了诱发读音、词汇和语法变化的动因，尝试回答语言为什么必然会变化的问题。
