Learn Croatian: Ne znam o kome pričate jer je ovdje jako bučno. - I do not know whom you are talking about because it is very noisy here.

kome is the locative case of the interrogative pronoun tko (who). The preposition o (about) always requires the locative case when you are talking or thinking about someone or something.

In English we say "whom you are talking about". Can I put the preposition o at the end of the clause in Croatian?

No, unlike in English, Croatian never leaves prepositions dangling at the end of a sentence or clause. The preposition must always go right before the pronoun it affects, making it o kome (literally "about whom").

Why does the word for noisy end in "-o" (bučno)?

This is an impersonal construction. When describing general conditions like the environment (such as "it is noisy" or "it is cold"), there is no specific noun for the adjective to agree with. In these cases, Croatian defaults to the neuter singular ending, which is -o.

Could I use govorite instead of pričate here?

Yes, they are very often interchangeable. However, pričati feels a bit more like "conversing" or "chatting", which perfectly fits the context of people having a casual conversation in a noisy place. govoriti can sometimes lean slightly more towards the physical act of "speaking" or giving a speech.