"Laat asseblief 'n boodskap"
However, this sounds a bit formal. In a more casual setting, you could use:
"Los asseblief 'n boodskap"
Here are some other options, depending on the context:
* "Spreek asseblief na die toon" (Please speak after the tone)
* "Laat 'n boodskap asseblief" (Leave a message please)
* "Jy kan 'n boodskap los" (You can leave a message)
Remember that Afrikaans pronunciation is fairly straightforward, and most words are spelled as they sound.