I can't find an email address to contact Duolingo, could you please help?
Also I started a competition withing my school, for students to get as many XP as they can. How can I set up different languages for them to choose? I'd like them to practise as many as they wish.
ok - you may wish to check out the advice in: https://support.duolingo.com/hc/en-us/articles/115002571143-How-can-I-contact-Duolingo-for-Schools-
Please be aware - I am a volunteer here. I do not work for Duolingo.
This is great news that you have started a competition for XP in your school.
I do not know if these resources about them being able to choose their own languages may assist you:
This article may also be of interest:
Duolingo does not have a public email address that they monitor. They have a handful of employees and a user base in the tens of millions. Maybe if you said what you needed to contact them for, we could give you some suggestions.
In "normal" Duolingo, you can add languages by hovering over your name and then clicking Settings -> Learning language. I'm not sure how this would play with Duolingo for Schools, though, since each classroom can only be associated with one course (the last time I looked).