Okay, as someone who studies language and intercultural learning in telecollaboration and study abroad focusing on U.S. Arabic learners (and interviews their Arab partners as part of my research) I have a lot to say about this 🙂
1) #1 is definitely a concern for U.S. learners even pre-Trump, especially when partnered with the Arab world. It’s as you suggested a major motivator for Arabs to participate, I can’t think of a single participant who hasn’t listed it as a reason.
2) I actually think this sentiment in both parties + the idea of “East-West” exchanges in a way reinforces the divide by not being critical about how this is presented (not that I think they should stop or there aren’t differences, but this is too dichotomous if that makes sense)
3) You should absolutely mix languages as needed in exchanges. This is normal multilingual behavior—(like at AUC where there’s not a dialect divide!) 3aadii! English only helps no one, including Arabic learners, or U.S. learners who need to be exposed to multilingualism.
And probably I should stop there, but I could discuss this topic forever 🙂