Can I learn more than one language on Langua? And does it cost more to do so?

You can switch between languages and there's no extra cost for learning multiple languages.

Go to Learning Settings and change the language, then save (it'll autosave if using the mobile app). At present, if your level varies by language, you will need to adjust it manually.

In the mobile app, you can also tap the flag towards the top right of the homepage to easily switch languages.

Due to the way Langua is set up, if you don't want to bother switching language each time, you can simply return to past conversations via the History page. There, you'll see chats from all languages. If you open one, the settings from the chat will override your account settings. This means that you can return to a previous conversation without updating the settings and it'll still work - translations will be in the right language. If you save vocabulary, it'll be saved to the right language.