it’s regulation for all international airports and airlines. icao doc 10086. english followed by the native language of the host cuntry. whereas iata recommends that engrish be used universally for travel announcements. icao sets the standards for air travel and is the sole authority under the un charter. iata is only a trade organization and recommends best practices. major airports normally have announcers at the pa or all-terminal level with bilingual ability. but not all gate agents are bilingual or fluent in the local tongue. if a gate agent who speaks local language cannot be found, english must still be used for any announcements by default. most major airports will have announcements in several languages. at haneda you’ll hear at least 3: engrish, jap, chink. it depends on the passenger composition at the airport. eventually in changi there’ll be hindi announcements. namaste! welcum to ceca island.