GNOME’s help is being translated by a world-wide volunteer community, and there are many languages for which translations are still needed.
To start translating, create an account and join the translation team for your language. This will give you the ability to upload new translations.
Connect with other GNOME translators in the #i18n:gnome.org Matrix room. See the Get help with Matrix page for more information. If you prefer, there is also an IRC channel, #i18n, on the GNOME IRC server. As the people in these rooms are located across the world, it may take a moment to get a response.
Alternatively, you can contact the Internationalization Team using their mailing list.