In American English, can we say either of these sentences interchangeably?
The sound of what is this?
This is the sound of what?
Context: Imagine I heard a sound at home which sounds like it is coming from a device in the kitchen, and I am wondering the sound of what device it is.
My opinion: I think either of these sentences can be used interchangeably. But the second sentence I gave has more of an informal structure I guess.
Note: I am asking this question of Americans because I've been learning American English and there can be a lot of differences between American and British English. No offense to British English. :)