I flew a lot of flights on United where they have a feature in the inflight entertainment system where you can listen in on the ATC comms (if the captain turns

I flew a lot of flights on United where they have a feature in the inflight entertainment system where you can listen in on the ATC comms (if the captain turns it on). I've found that: * French pilots generally speak in French in France or Quebec * Russian pilots speak in Russian in Russia * Mainland Chinese pilots speak in Mandarin in mainland China (but not in Taiwan or HK where English seems to be universal) * Spanish/Latin American pilots speak in Spanish in those places. Otherwise, it's generally English ATC including countries where it's otherwise not the native language, e.g. Japan, South Korea, Germany.