Upali žmigavac prije nego što skreneš lijevo.

Upali is the imperative singular of upaliti.

In everyday Croatian, upaliti does not only mean to light or to set on fire. It is also very commonly used to mean:

• turn on
• switch on
• activate

So in this sentence, Upali žmigavac means Turn on the turn signal / indicator.

This is very natural Croatian. You may also hear uključi žmigavac, which is similar, but upali is extremely common in speech.

Yes, žmigavac is a very common everyday word for a turn signal / blinker / indicator.

It comes from the idea of something that blinks or flashes.

Some related words you may also see are:

• žmigavac = everyday spoken word, very common
• pokazivač smjera = more formal, literally direction indicator

So Upali žmigavac sounds natural and idiomatic in everyday Croatian.

Prije nego što means before in the sense of before you do something.

It introduces a clause:

• prije = before
• nego što = than / that, as part of this fixed expression

So:

• prije nego što skreneš lijevo = before you turn left

You should learn prije nego što as a set phrase, because it is very common.

This is a very common point for English speakers.

After conjunctions like prije nego što, Croatian often uses the present tense form of a perfective verb to refer to a future action.

Here:

• skrenuti = perfective verb, to turn (complete action)
• skreneš = present-tense form, 2nd person singular

Even though it looks like a present tense form, in this kind of clause it refers to a future event:

• prije nego što skreneš lijevo = before you turn left

So Croatian does not need a future form here.

Skreneš comes from skrenuti, which means to turn, to make a turn, or sometimes to deviate depending on context.

Here it is specifically about driving:

• skrenuti lijevo = to turn left
• skrenuti desno = to turn right

The form skreneš is:

• 2nd person singular
• from the present-tense paradigm
• used here after prije nego što

Because lijevo here works as an adverb, meaning left in the directional sense.

Croatian normally says:

• skrenuti lijevo = turn left
• skrenuti desno = turn right

This is similar to English, where we also just say turn left, not turn to left.

So lijevo here is the normal and correct form.

Croatian usually does not need subject pronouns when the verb already shows who the subject is.

Here:

• upali = imperative singular, so it already means you (singular), turn on
• skreneš = you turn

Because the verb endings already show the person, adding ti is usually unnecessary unless you want emphasis.

So:

• Upali žmigavac prije nego što skreneš lijevo. = normal
• Ti upali žmigavac... = possible, but more emphatic

It is talking to one person.

You can tell from the verb forms:

• upali = singular imperative
• skreneš = 2nd person singular

If you were speaking to more than one person, you would use plural forms, for example:

• Upalite žmigavac prije nego što skrenete lijevo.

That means Turn on the turn signal before you turn left when speaking to more than one person, or formally to one person in some contexts.

Yes, it matters.

Upaliti is a perfective verb. It focuses on the action as a completed whole: turn it on.

Its imperfective partner is usually:

• paliti = to be turning on / to turn on habitually / repeatedly

In an instruction like this, Croatian strongly prefers the perfective imperative because the speaker wants one complete action:

• Upali žmigavac = Turn on the signal
• not the ongoing process, but the completed activation

The same is true with skrenuti:

• skrenuti = perfective, make the turn
• in this sentence the completed turning event is what matters

Yes. That is also natural.

• upaliti žmigavac = turn on the turn signal
• uključiti žmigavac = turn on / activate the turn signal

Both work. In everyday speech, upaliti is often very common for devices, lights, engines, and signals.

So the original sentence is very idiomatic, but uključi is also correct.

Yes, Croatian word order is flexible, but the original order is very natural:

• Upali žmigavac prije nego što skreneš lijevo.

This puts the instruction first and then the time clause.

You could also hear:

• Prije nego što skreneš lijevo, upali žmigavac.

That means the same thing, but it emphasizes the before turning left part first.

So both are correct. The original version is simple, direct, and very natural for an instruction.

In this expression, što is part of the fixed conjunction prije nego što.

In modern standard Croatian, learners should generally use the full form:

• prije nego što skreneš

In some contexts or styles, you may encounter shorter variants, but prije nego što is the safest and most standard choice to learn and use.

So for a learner, it is best to treat prije nego što as one chunk meaning before.

A more formal version might use pokazivač smjera instead of žmigavac:

• Uključite pokazivač smjera prije nego što skrenete lijevo.

That sounds more like something from a manual, lesson, or official instruction.

The original sentence:

• Upali žmigavac prije nego što skreneš lijevo.

sounds more everyday and conversational, like something a driving instructor, parent, or friend might say.

A rough pronunciation guide is:

• žmigavac ≈ zhmee-GAH-vats

A few notes:

• ž sounds like the s in measure
• stress is usually on GA
• c at the end sounds like ts

So approximately:

• zhmee-GAH-vats

That said, listening to native audio is the best way to get the sound and rhythm right.