I would like to ask about the details of the visa interview at the US Embassy, ??thank you! ! Do I have to speak English during the interview?

You do not need to speak English for the visa interview. The visa officer can speak Mandarin fluently. If you are traveling, it is recommended not to speak English. For other visas, it depends on whether speaking English will help you get the visa. Just answer the questions asked by the visa officer truthfully during the interview. You must be familiar with all the information you submitted. During the visa interview, the first impression of the visa officer is very important. You should dress appropriately, speak naturally, and show your confidence.