Breakdown of Ne znam čiji sam dnevnik pronašao.
biti
to be (sam, si, je)
ne
no, not
znati
to know
pronaći
to find
Questions & Answers about Ne znam čiji sam dnevnik pronašao.
What case is čiji dnevnik in, and why doesn't čiji end in -g?
It is in the accusative case because it is the direct object of the verb pronašao (found). Čiji (whose) acts like an adjective and must agree with the noun it describes. Since dnevnik (diary) is a masculine inanimate noun (a non-living thing), its accusative form looks exactly like the nominative form. If you were talking about a living thing, you would use the animate ending, such as čijeg psa (whose dog).
Why is the helper verb sam wedged between čiji and dnevnik?
The word sam is an enclitic, which is a "weak" word that strictly belongs in the second grammatical position of its clause. The second half of this sentence is a new clause that starts with the question word čiji. Because enclitics insist on being second, sam must immediately follow čiji, even if it interrupts the phrase čiji dnevnik.
Why use pronašao here instead of nalazio?
Pronašao is a perfective verb, meaning it describes a single, completed action (you discovered the diary). Nalazio is an imperfective verb, which would mean you were in the ongoing process of finding it, or you found it repeatedly. Since finding a specific diary is a one-time event, the perfective aspect is required.
Is dnevnik only used to talk about a personal diary?