/etc/locale.gen

/etc/locale.gen contains the locale definitions and system languages.

Every line that does not begin with a # is treated as a locale definition to be built by the shell script /usr/bin/locale-gen. This script reads locale.gen and invokes localedef for the chosen localisation profiles and places the generated locales in /usr/lib/locale.

The format of uncommented lines in the file is <locale-name> <charset>, for example

en_US.UTF-8 UTF-8
de_CH.UTF-8 UTF-8