In theory, the only parts of the backend code where you need localization is the settings declaration and standardized data (ActivityPub, RSS, ...).Here we need to get english strings from the translation key.
There is a specific "Hugo shortcodes" you can use to display an application string.Saying you want to display the name of the button "open_chat_new_window", you can use this in the documentation markdown file:
If a string contains a link, you can change it for the correct link in the translated language.For example, for a link to this documentation, you can add the language code in the url.