Building multi-lingual websites can pose challenges at the best of times. GatherContent can soothe these pains using multiple tabs as part of item structures, or separate projects.
For example, you could structure the first tab of an item with all fields for your primary language such as English. This is sometimes called source content or simply the name of the language.
You can then add another tab to your item's structure. The copy can be renamed as needed such as Content French, or whatever your next language may be.
The benefit of this is that your team can add secondary languages to the same item in GatherContent. Each tab would have the same layout so it's easy for the team to follow what should be where on the page.
Entire projects can also be duplicated. By selecting the gear icon in the projects view, you can then select 'duplicate project'. This duplicates all items, structures, templates and content. So you can easily duplicate the entire project and then translate every field into the different language or languages required.
In this case, it is a good idea to use word and character limits so the volume of content produced for each field is consistent across different languages, or at least relatively similar, this helps keep the design work consistent across all languages too.