Learn Hardcore Hungarian: A színház előtt hosszú sor állt, mert népszerű volt a darab. - In front of the theatre a long line stood because the play was popular.

előtt is a postposition meaning in front of. In Hungarian postpositions follow the noun, which remains in the nominative (no extra case ending). The article A simply makes színház definite. So A színház előtt means in front of the theatre.

Why is hosszú used in its base form before sor? Shouldn’t it agree in number or definiteness?

Hungarian adjectives do not change form for number, case or definiteness. Whether the noun is singular, plural, definite or indefinite, the adjective stays in its basic form. That’s why hosszú sor (“long queue/line”) uses hosszú unchanged.

In hosszú sor állt, why is the verb állt (“stood”) used instead of volt (“was”) to convey “there was a long line”?

Both állt and volt can express existence, but with a nuance:

állt (“stood”) emphasizes the visible, upright formation of people in line.
volt (“was”) is more neutral, simply stating that a line existed.

Could you also say Hosszú sor volt a színház előtt? If so, is there any difference?

Yes. Hosszú sor volt a színház előtt is perfectly correct. It states that a long line was in front of the theatre. The difference is subtle:

sor állt paints a more concrete picture of people standing.
sor volt stays at the level of stating existence.

How does the conjunction mert function here, and how does it differ from mivel?

mert is a coordinating conjunction meaning because. It joins two clauses without changing word order.
By contrast mivel is subordinating:
• It often begins the sentence.
• It triggers a verb–subject inversion in the subordinate clause.
Example with mert:
“Hosszú sor állt a színház előtt, mert népszerű volt a darab.”
With mivel:
“Mivel népszerű volt a darab, hosszú sor állt a színház előtt.”

Why is the clause after mert ordered as népszerű volt a darab rather than mert a darab népszerű volt?

Hungarian allows flexible word order for emphasis. Putting népszerű (adjective) and volt (verb) before the subject a darab highlights the popularity as the main reason. If you say mert a darab népszerű volt, it’s equally correct but less focused on the adjective.

What function does volt serve in népszerű volt a darab?

volt is the past-tense form of lenni (to be). Here it links the predicate adjective népszerű (“popular”) to the subject a darab (“the play”), yielding the play was popular.

Why is darab used to mean “play”? Doesn’t it usually mean “piece”?

Literally darab means piece, but in theatre contexts it refers to a stage piece—that is, a play. The definite article a specifies that it’s the play in question.

Why does the sentence start with A színház előtt rather than with Hosszú sor állt?

Hungarian often uses a topic–comment structure. Placing the location A színház előtt first sets the scene (topic) and then comments on what happened there. It helps the listener know the context before hearing about the line.

Could you rearrange the main clause as Hosszú sor állt a színház előtt? Would it still be correct?

Yes. Hosszú sor állt a színház előtt is also grammatically correct. Whether you lead with the location (A színház előtt) or the subject-verb phrase (Hosszú sor állt) depends on what you want to foreground: the place or the event.