Localization (a.k.a. l10n) is the process of improving the experience of non-English speaking users of a Synchronet BBS.
ctrl/text.lang.ini file can be used to replace text.dat strings/substrings with translated/localized strings/substringstext/menu/lang/* files can be used to replace menu files with translated/localized equivalents[JS] section of ctrl/text.lang.ini files can be used to replace any JavaScript strings that are passed-to/returned-from gettext() (see load/gettext.js)