The GNOME client's chatview lacks proper i18n support.
Related bug report: ring-client-gnome#900 (closed)
C++ tells JS code which language is currently used and JS code loads translations
C++ loads translations and passes them to JS code together with info about currently used language
This will require translation of .po files to JSON format (using i18next-gettext-converter).
This will require translation of .po files to JSON format (e.g. using po2json).
po2json also requires nodeJS as dependency, but it is available as Debian package, which makes it slightly less annoying
$ cd po/chatview
$ cp ring-client-gnome-chatview.pot en.po
$ cp ring-client-gnome-chatview.pot fr.po
# translate ...
$ apt-get install node-po2json
$ ./scripts/build-chatview-locales.sh web/i18n
That's it. JSON translations are loaded as gresource. The webkitchatcontainer class calls init_i18n(), passing appropriate translation resources to the chatview.