When you create a new push or in-app campaign, the editor allows you to create notifications in several languages. The default language is the fallback language used in your push and In-App campaigns. All your campaigns must contain a version of your message in the default language of your app.
You can add languages, clicking on "+". Batch will automatically send the message in the right language to every targeted users.
1- If you are sending a campaign in one single language, you can write your push directly on the first tab, even if the language is not corresponding.
For instance, as shown above, I can write my push in English even if French is set as the default language. Since it's only one push, the latter is my "default" message.
2- If you are sending a campaign written in different languages, choose one default language, then create many notifications in other languages.
Batch will deliver the message in the default language if you don’t have a message in the language of a user.