What's the closest you can get to speaking in dialup sounds?

Vaguely related: there are people who whistle conversations in many mountainous regions in the world.

- https://www.youtube.com/watch?v=PTHzOag8msM

- https://www.youtube.com/watch?v=TfGwFM9-wFk

- https://www.youtube.com/watch?v=6CYhRsU4F34

I could once whistle close enough to handshake tones to make 1200 and 2400 baud modems start talking in a 1200 baud mode.

There's various audio codecs which can encode arbitrary data. you could hook something like this: https://bellard.org/linmodem/ up to whatever microphone and digitization and encoding chain you wanted; just for sheer perversity.