Breakdown of Ne treba mi tvoj potpis za svaki dokument.
ne
no, not
tvoj
your (informal)
trebati
to need / should (ought to)
za
for / at (a table) (+ instrumental)
Questions & Answers about Ne treba mi tvoj potpis za svaki dokument.
Why does this sentence use mi (to me) instead of "ja" (I) with the verb trebati?
In Croatian, when you need a noun (like a signature), trebati is often used in a structure that translates literally as "X is needed to me." The person who needs something is in the Dative case (mi), and the thing needed is the grammatical subject. You will also sometimes hear people say "ja ne trebam", which uses trebati as a normal personal verb, but the Dative structure used in this sentence is extremely common and natural.
If mi isn't the subject, what is controlling the verb treba?
The grammatical subject is tvoj potpis (your signature). Because potpis is a singular third-person noun, the verb is in the third-person singular form: treba. If you needed multiple signatures (potpisi), the verb would change to match the plural subject: Ne trebaju mi tvoji potpisi (Your signatures are not needed to me).
Why doesn't the ending of svaki dokument change after the preposition za?
The preposition za (for) requires the Accusative case here. Because dokument is a masculine inanimate noun (an object, not a living being), its Accusative form is exactly the same as its base dictionary form. The adjective svaki (every) follows the same rule, so it looks like it hasn't changed either!
Why is the word mi placed right after Ne treba?