Learn Hardcore Croatian: Zašto će restoran biti zatvoren?

Zašto = why (interrogative adverb)
će = will (future auxiliary; short/clitic form of htjeti)
restoran = restaurant (masculine singular, nominative subject)
biti = to be (infinitive)
zatvoren = closed (past passive participle functioning as a predicate adjective, masculine singular to agree with restoran) Literal structure: Why + will + restaurant + be + closed?

Why do we need biti (to be) before zatvoren?

Because you’re linking the subject to a predicate adjective/participle. Zatvoren on its own isn’t a verb; biti supplies the verb “to be.” Saying Restoran će zatvoren is ungrammatical; you need biti: Restoran će biti zatvoren.

Is this passive voice or just describing a state?

It can express either:

a future state: “the restaurant will be in a closed state,” or
a passive action (without naming the agent): “the restaurant will be closed (by someone).” To emphasize the closing event, use the reflexive: Restoran će se zatvoriti (The restaurant will close). To name the doer, use active: Vlasnik će zatvoriti restoran (The owner will close the restaurant).

Why masculine zatvoren, not zatvoreno?

Agreement. Restoran is masculine singular, so the predicate must be masculine singular: zatvoren. Other forms:

feminine: zatvorena (e.g., trgovina je zatvorena)
neuter: zatvoreno (e.g., on a door sign: Zatvoreno)

How is the future formed with će?

Croatian Future I = clitic forms of htjeti + infinitive:

ću, ćeš, će, ćemo, ćete, će
- infinitive (here: biti). Example: Restoran će biti zatvoren. In statements (not starting with a question word), you’ll also see the auxiliary after the infinitive with the -i dropped: vidjet ću (I’ll see), bit ću (I’ll be).

Can I say Zašto restoran će biti zatvoren?

No. Će is a clitic that normally goes in second position in the clause. Since Zašto is the first element, the clitic must come right after it: Zašto će restoran biti zatvoren?

Are variants like Zašto će biti zatvoren restoran? or Zašto će biti restoran zatvoren? acceptable?

Yes, they’re grammatical and put stylistic focus on the predicate. The neutral, most common version is still Zašto će restoran biti zatvoren?

What’s the difference between Zašto je restoran zatvoren? and Zašto će restoran biti zatvoren?

Zašto je restoran zatvoren? = Why is the restaurant closed (now)?
Zašto će restoran biti zatvoren? = Why will the restaurant be closed (at some future time)?

How do I negate it?

Use ne + će = neće:

Zašto neće restoran biti zatvoren? = Why won’t the restaurant be closed? Keep the clitic (ne)će right after the initial element in a question (here, after Zašto).

Can I omit the noun and just say something like “Why will it be closed?”

Yes, if context makes the referent clear: Zašto će biti zatvoreno? Here the neuter zatvoreno is used impersonally (“it will be closed”).

What’s the difference between zašto and za što?

zašto (one word) = why.
za što (two words) = for what (used with the preposition za meaning “for”), e.g., Za što je ovo? (What is this for?)

Are there other ways to ask “why,” like zbog čega or kako to da?

zbog čega = “because of what,” essentially “why,” a bit more formal/explicit about cause: Zbog čega će restoran biti zatvoren?
kako to da ≈ “how come,” more colloquial and often expresses surprise: Kako to da će restoran biti zatvoren?

What’s the difference between zatvoren, zatvaran, and related forms?

zatvoren = closed (result/state; past passive participle of perfective zatvoriti).
zatvaran = being closed repeatedly/typically (passive participle of imperfective zatvarati). Restoran će biti zatvaran suggests repeated or habitual closure (e.g., every weekend), not a one-off planned closure. Antonym: otvoren (open).

How do I add the agent, like “by the health inspector”?

Use od + Genitive (often with strane): Restoran će biti zatvoren od (strane) inspekcije. In everyday style, many just name the agent in a prepositional phrase: zbog inspekcije (because of the inspection).

Any article to mark “a” vs “the” in restoran?

Croatian has no articles. Restoran can mean “a restaurant” or “the restaurant” depending on context. Word order and context usually signal definiteness.

Pronunciation tips for the sentence?

š in Zašto = “sh” in “shoe” (za-sh-to).
će has a soft “ch” sound: roughly “che,” but lighter/softer than English “ch.”
Vowels are pure: a as in “father,” o like short “aw,” i like “ee.”
r is tapped/flapped; v is like English “v.” So: za-sh-to che res-to-ran bee-tee za-tvo-ren.