Question about international keyboards

If you’re in an English speaking country your default Android keyboard will be English.

If you’re in say Japan, is your keyboard in Japanese?

If you’re in Spain is it in Spanish (which has nearly all the English characters plus a few unique ones).

If you’re in Greece, is your keyboard in Greek?

And so on.

The reason I ask is because I want to create a chat app which will pair users who speak the same language together. The app itself will be in English so user will need a basic knowledge of English to use it. However, they can select a language that the person they will be paired up should speak.

This way people will be paired up with others who speak the same language.

But this will only work if the default Android keyboards are localised depending on the country a user is in.