本章重点为语言变体的分类、语言正式程度的等级划分、语言接触、禁忌语和委婉语以及交际能力。本章难点为海姆斯的交际能力说与乔姆斯基的语言能力说之间的区别。具体要点如下：

Chapter 9 Language in Society

Sociolinguistic study of language

Branch of linguistics which studies just those properties of language and languages which require reference to social, including contextual, factors in their explanation.

Varieties of language

The standard variety

A regional dialect

Sociolects

Register: field, mode and tenor

Grades of formality

Frozen Formal Consultative Casual Intimate

Language in contact

Pidgin: the label for the code used by people who speak different languages.

Creole: a mixed language which has become the mother tongue of a speech community. •

Bilingualism and multilingualism: Bilingualism gives rise to code-switching and code-mixing.

Taboos and euphemisms

Taboo: a prohibition on the use of, mention of, or association with particular objects, actions, or persons.

Euphemism: an expression that substitutes one which may be seen as offensive or disturbing to the addressee.

Competence

Linguistic competence: grammaticality presented by Chomsky

Communicative competence: four components presented by Hymes 

学习了这些内容后，相信大家对语言和社会有了更深入的了解，这将有利于大家今后的英语的学习。

如果想要了解更多关于如何学习章节的内容，请在学习资源继续了解本章拓展内容。