The language of the interview should be appropriate to the conversation/question we were given.

My language is Serbian/Croatian, I often have a situation where I get questions in my native language during the interview, and then in the second part of the interview I get questions in English. In those situations, if we choose one language before the interview itself, then I don't get the answers when it switches to English or vice versa -> the interview starts in English and then switches to my native language.