The language barrier can make things difficult sometimes and some students lack the awareness and English skills necessary to communicate with ATC. That being said a lot of times it’s the instructors fault for not allowing them to do radio calls in the first place so they end up in their instrument stage scared to death to talk to ATC. I would say it’s a little more nerve racking sending them on solos but they only fly be themselves in private curriculum so most of the time theirs a CFI in the right seat watching out for traffic and constantly helping them with whatever they need work on.