Learn Croatian: Znaš li cijenu automobila? - Do you know the price of the car?

Automobil is a masculine noun. In this sentence, it is in the genitive case, which is often used to mean "of" something. To form the genitive singular of a masculine noun, we add -a to the end, making it automobila (of the car).

Why does the word for price end in -u (cijenu)?

The dictionary form of the word is cijena, which is a feminine noun. Here, it is the direct object of the verb znaš (you know), so it must be in the accusative case. Feminine nouns ending in -a change their ending to -u in the accusative.

What is the purpose of the word li?

li is a question word (a particle) used to ask yes/no questions. A very common way to ask a question in Croatian is to put the verb first, followed immediately by li. So, Znaš li... means "Do you know...".

Why isn't the word for "you" (ti) included in this sentence?

In Croatian, the verb ending already tells us who is doing the action. The -š at the end of Znaš specifically means "you (singular) know". You would only add ti if you wanted to add special emphasis.