Merge branch '6.0' into restapi-enable-discussions

Author: stevepiercy

docs/i18n-l10n/index.md

@@ -27,6 +27,17 @@ Wikipedia article [Internationalization and localization](https://en.wikipedia.o
 ```
 
 
+(i18n-l10n-supported-languages)=
+
+## Supported languages
+
+Plone supports many language translations in its two frontends.
+For Volto, see [`plone/volto`](https://github.com/plone/volto/tree/main/packages/volto/locales).
+For Classic UI, see [`collective/plone.app.locales`](https://github.com/collective/plone.app.locales/tree/master/plone/app/locales/locales).
+
+You can contribute new languages to both frontends.
+
+
 (i18n-l10n-code-versus-content-label)=
 
 ## Code versus content