- Internationalization (i18n) is a set of mechanisms to make it possible to translate (localize) CiviCRM to other languages without changing code.
- Localization (l10n) refers to using CiviCRM in another language than US English. This includes translating the text of the user interface, but also date, currency and other settings.
- Multiple language support (multilingual): in CiviCRM jargon, this means that the CiviCRM instance supports multiple languages at once, such as bilingual or trilingual sites (ex: using the same contribution form in English and Spanish, where the title, intro text, etc must be bilingual). This means that not only the user interface must be translatable, but also some of the configurations, such as the contribution form title, description, etc.
This documentation is being migrated to Gitlab:
Administrator guide: Using CiviCRM in your own language