[bobthepanda]

In a lot of modern buildings in Hong Kong, lifts announce floors in three languages: English, Cantonese, and Mandarin.

I'd imagine in Macau, they might use four (those three plus Portuguese); the public transit stop announcements do, and quite frankly I'm not sure how they guarantee that they can complete the announcements before the next stop.

[burfog]

At that point, just use Morse code. For small buildings, the cuckoo clock method works too.

[bobthepanda]

the main reason why elevators in Hong Kong do not is that most of them are high speed high-rise elevators and the numbers just whip by. It would probably be very frantic sounding to use Morse if you went from ground to 50 in less than a minute.

Instead they only announces floors that are stopped on, so this works fine.

One benefit of using spoken vernaculars rather than Morse is that Morse has to be taught; Hong Kong historically draws large portions of its population from migrants originating from all over China, where until recently there was wide variance in schooling and literacy rates.