Can we say “The sound of what is this?” or “This is the sound of what?” (American English)

Question

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. :)

Answer 1

The first sentence is ungrammatical.

The second sentence is awkward without further context, such as the following:

"Say that again? This is the sound of what?"

A more common way of phrasing such a question would be something different:

What's making that sound?

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Note that it wouldn't normally sound right to ask about this sound. It would more often be phrased that sound. If you're talking about this, you're typically talking about something close to you in location or concept. If it's an unidentified sound, it would be that.

Answer 2

EDIT:

In AmE, we would not ask the question in the first way, The sound of what is this? We would say

What's this the sound of?

We could also ask:

This is the sound of what?

if we were about to play a sound recording, say. If we had just played the recording, we might ask:

That was the sound of what?

Answer 3

Normal conversational language would be "What is making this sound?"

Your second example, "This is the sound of what?" is something you might find on an exam or game show question, but not in common usage.

Your first sentence, "The sound of what is this?", would only be uttered by Yoda.