Each page and CMS entry is translatable. When creating fields for a Collection, mark whether that field is translatable (some fields won't need translation, like references to other collections, price fields, etc).
An option for Links should be added to choose a language (in addition to external links, pages within the site, etc).
While we have designs ready and validated for creating multi-language sites, we’ve paused work on this project while we focus our energy on some infrastructure-heavy projects needed to make the platform more stable — both in the short and long term. We’re still aiming to release features that will improve workflows for multi-language sites in 2019.