Sure.

Case:
Imagine you are a native Spanish speaker and so is your customer and let's say you are an expert in finance. You can choose to teach in Spanish, of course. Why not?

Case:
Imagine you wanted to teach French to Students whose mother tongue is Japanese. That should be possible. But do make sure to set a "required minimum English level" on your Course to ensure your Japanese customer can communicate with you in case they can't express themselves enough in French. There must always be a common language for you to communicate with your customers. And as a Teacher, this is "your" responsibility.

Good to know:
When Students sign up on our platform, they must set their English level.
Also, you can add up to 4 translations of your Course description on your Course page to attract customers who speak those languages. Another great marketing strategy.