Here are entered works on the simultaneous coexistence of two forms of the same language in a speech community. Works on switching from one language to another by bilingual members of a speech community are entered under the heading Code switching (Linguistics).
Here are entered works on the continued use of a language in a multilingual setting, especially when in competition with culturally or numerically more influential languages.
Here are entered works on planned language change directed towards improving communication within a society. Works on government language policy are entered under Language policy.