この騒音はなんだ？

この騒音はなんだ？

What's this noise?

この騒音(そうおん)はなんだ？

Kono sōon wa nan da?

此の (この)

this (something or someone close to the speaker (including the speaker), or ideas expressed by the speaker)

騒音 (そうおん)

noise

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

何 (なに、なん)

what; how many; you-know-what; that; whatsit; what's the expression; what do you call them; what?; hey!

だ (だ)

be; is; indicates past or completed action; indicates light imperative

Readings: ソウ、さわ.ぐ、うれい、さわ.がしい

Meanings: boisterous, make noise, clamor, disturb, excite

Readings: オン、イン、 -ノン、おと、ね

Meanings: sound, noise