Eğer yangın büyüseydi, itfaiye daha fazla ekip çağırmak zorunda kalacaktı.

A helpful breakdown is:

• Eğer = if
• yangın = fire
• büyüseydi = if it had grown / gotten bigger
• itfaiye = the fire department / fire brigade
• daha fazla ekip = more teams / more crews
• çağırmak zorunda kalacaktı = would have had to call

So the whole sentence means something like:

If the fire had grown, the fire department would have had to call more crews.

No. It is optional.

Turkish already shows the conditional idea with -se/-sa, so:

• Eğer yangın büyüseydi, ...
• Yangın büyüseydi, ...

both mean If the fire had grown, ...

Using eğer just makes the if meaning more explicit.

Büyüseydi is built like this:

• büyü- = verb stem from büyümek = to grow, become bigger
• -se = conditional marker
• -ydi = past element

So büyüseydi means if it had grown.

This is a very common Turkish way to make a past unreal condition. In English, we usually use if + had + past participle. Turkish does it with this single combined form.

This is a past unreal / counterfactual conditional.

It talks about a situation that did not happen, or is being presented as contrary to fact:

• If the fire had grown, ...
• ... the fire department would have had to call more crews.

So the pattern is basically:

If X had happened, Y would have happened.

In Turkish, that often looks like:

• if-clause: -seydi / -saydı
• main clause: often -acaktı or sometimes -rdı

Yes. Very naturally.

In Turkish, a fire can büyümek, literally grow. In English, we might more often say:

• the fire spread
• the fire got bigger
• the fire got worse

But in Turkish, yangın büyüdü is completely normal.

It breaks down like this:

• çağırmak = to call
• zorunda = under obligation / obliged
• kalmak = to remain, stay, end up
• kalacaktı = would end up / would be in the situation of

Together, çağırmak zorunda kalacaktı means:

would have had to call

So the idea is not just simple intention. It means the fire department would have been forced by the situation to call more crews.

There is a small nuance:

• zorunda olmak = to be obliged / to have to
• zorunda kalmak = to end up having to / to be forced to

So:

• çağırmak zorunda olmak = to have to call
• çağırmak zorunda kalmak = to end up having to call because of circumstances

In this sentence, the fire getting bigger would create that necessity, so kalmak sounds very natural.

Because after numbers and quantity expressions, Turkish usually keeps the noun in the singular.

So Turkish says:

• iki kitap = two books
• çok insan = many people
• daha fazla ekip = more teams

Using ekipler after daha fazla would usually sound unnatural.

Also, ekip is an indefinite direct object here, so it stays in the bare form rather than taking the accusative ending.

Because the sentence is talking about some additional teams, not a specific, already-identified set of teams.

In Turkish, indefinite direct objects usually stay bare:

• ekip çağırmak = to call teams / to call a team
• daha fazla ekip çağırmak = to call more teams

If you meant specific teams, then a marked form like ekipleri could appear, but that is not the meaning here.

İtfaiye usually means:

• fire brigade
• fire department
• sometimes, by context, firefighters

In this sentence it works as a collective singular noun, so the verb is singular too:

• itfaiye ... kalacaktı

Even though it refers to a group of people, grammatically it behaves like a singular institution.

Because Turkish does not have a definite article like English the.

So Turkish often just uses the noun by itself:

• yangın
• itfaiye

English needs the fire and the fire department, but Turkish relies on context instead of a separate word for the.

Not completely, but this order is very natural.

Turkish commonly puts the conditional clause first:

• Eğer yangın büyüseydi, ...

and then the result clause:

• itfaiye daha fazla ekip çağırmak zorunda kalacaktı.

The sentence also follows a normal Turkish pattern where the verb comes near the end.

The comma is also normal in writing because it separates the if-clause from the main clause.