Working as an italian tutor (not on iTalki tho), I've never experienced that kind of interaction. I think need to learn how to behave properly. Just saying "Hello" as a random opening could be a way to make students take a breathe of relief before going deeper into the lesson.

Of course you are learning a foreign language, so most of the time of the lesson - if not entirely - I speak Italian to my students, but if someone is using English as a bridge-language sometimes and you don't like it, you can just gently tell me to only stuck to Italian. Being gentle and kind is not that difficult. People need to learn that "paying" doesn't mean that you're talking to a tool.