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).
We’re nearing the end of our planning process for multi-language support, and have initial designs that we’re testing and collecting feedback on before building. Development planning has begun on the back end infrastructure, and front end teams will start work as soon as our designs have been validated. With all this in motion, we’re aiming to release multi-language support in 2019.