It is adapted to other languages: in French in France, “Hey Siri” becomes “Dis Siri” (meaning about the same as “hey” with the additional meaning in this case too of “tell me, Siri”).Absolutely - the trigger words should be less US-Centric as well (perish the thought). English people certainly dont go around using the word "Hey" in the manner that we are expected to for Siri - and definitely not out loud and in public - its embarrassing.
My toddler does know enough however to say "Hey Siri - why are you rubbish" when it fails (yet again) to play a simple playlist.
In Japanese they kept “Hey” though… (“Hey Shiri”).
So I suppose it depends on the language (or country).