I looked it up and it's not just one language: there are numerous languages across the world that use whistling in their speech.
@witchfynder_finder I was just about to reply with this! it's pretty neat!
@witchfynder_finder there's a typology class at my uni!
@lizardsquid I think we had a phonological typology course? Maybe? But if we did it was taught by the professor I absolutely couldn't stand so either way I missed out. ;A;