language_negotiation_configure_url_form in core/modules/locale/locale.admin.inc

Builds the URL language provider configuration form.

locale_enable in core/modules/locale/locale.install

Fill in the path prefixes and domains when enabled.

locale_language_delete in core/modules/locale/locale.module

Implements hook_language_delete().

locale_language_from_url in core/includes/locale.inc

Identify language via URL prefix or domain.

locale_language_insert in core/modules/locale/locale.module

Implements hook_language_insert().

locale_language_url_fallback in core/includes/locale.inc

Determines the language to be assigned to URLs when none is detected.

locale_language_url_rewrite_url in core/includes/locale.inc

Rewrite URLs for the URL language provider.