nixpkgs/doc/builders/packages/locales.section.md

Locales

To allow simultaneous use of packages linked against different versions of glibc with different locale archive formats, Nixpkgs patches glibc to rely on LOCALE_ARCHIVE environment variable.

On non-NixOS distributions, this variable is obviously not set. This can cause regressions in language support or even crashes in some Nixpkgs-provided programs. The simplest way to mitigate this problem is exporting the LOCALE_ARCHIVE variable pointing to ${glibcLocales}/lib/locale/locale-archive. The drawback (and the reason this is not the default) is the relatively large (a hundred MiB) size of the full set of locales. It is possible to build a custom set of locales by overriding parameters allLocales and locales of the package.