'get_language_from_request', 'get_language_info', 'get_language_bidi', 'check_for_language', 'to_locale', 'templatize', 'string_concat', 'gettext', 'gettext_lazy', 'gettext_noop', 'ugettext', 'ugettext_lazy', 'ugettext_noop', 'ngettext', 'ngettext_lazy', 'ungettext', 'ungettext_lazy', 'pgettext', 'pgettext_lazy', 'npgettext', 'npgettext_lazy' and 'LANGUAGE_SESSION_KEY'. LANGUAGE_SESSION_KEY is an string '_language'.
LANGUAGE_SESSION_KEY = '_language'