Learn Hardcore Croatian: Brzina je problem u prometu.

Meaning: The sentence is about speed; speed is what is being described as a problem.
Typical word order: Croatian often uses Subject – verb – complement, just like English, so Brzina je problem = Speed is a problem.
Case: Both brzina and problem are in the nominative case. With the verb biti (to be), both the subject and the noun that equals it are in the nominative.
- brzina – nominative singular feminine
- problem – nominative singular masculine

You could also say Problem je brzina, which still means Speed is the problem, but it puts more emphasis on problem (“The problem is speed”). Word order changes emphasis, not basic meaning.

Why is it brzina and not something like brz? What’s the difference?

Brz is an adjective meaning fast / quick.
Brzina is a noun meaning speed.

Croatian often forms abstract nouns from adjectives by adding endings like -ina:

brz (fast) → brzina (speed)
dubok (deep) → dubina (depth)
širok (wide) → širina (width)

In this sentence, you need a thing (a noun) that can be a problem, so brzina is used: Brzina je problem = Speed is a problem, not Fast is a problem.

Why is it u prometu and not u promet? What case is prometu?

Prometu is in the locative case (singular), used mostly after certain prepositions, especially u (in) and na (on), when talking about location (where something is).

With u:

Direction / movement into → accusative
- Idem u promet. = I’m going into traffic.
Location / being in → locative
- Brzina je problem u prometu. = Speed is a problem in traffic.

So in this sentence we’re talking about a situation within the sphere of traffic (a static context), so u + locative is used: u prometu.

What exactly does promet mean here? Is it only road traffic?

In Croatian, promet is broader than just “cars on the road”, but in this sentence it’s understood as road traffic / traffic in general.

Depending on context, promet can mean:

road traffic: cars, buses, trucks on streets and highways
traffic / circulation generally: pedestrian and vehicle movement
commerce / turnover (in business contexts):
- promet u trgovini – sales / turnover in a shop

In everyday talk about roads, promet usually means road traffic, so problem u prometu naturally reads as a problem in (road) traffic.

Why is there no word for the or a in the Croatian sentence?

Croatian does not use articles like English a / an / the.

Brzina je problem u prometu can correspond to:
- Speed is a problem in traffic.
- Speed is the problem in traffic.

Whether it feels like “a” or “the” is decided by context, not by a separate word.

Some rough guidelines:

A new, non‑specific problem → usually felt as a problem.
A specific, known problem you’ve already mentioned → may be understood as the problem.

But in Croatian, the sentence itself doesn’t change; only the context makes that distinction.

Why is the verb je and not something like jest or biti?

Biti is the infinitive “to be”.
Je is the third person singular present form “is”.

Present tense of biti:

ja sam – I am
ti si – you are (sg)
on / ona / ono je – he / she / it is
mi smo – we are
vi ste – you are (pl / polite)
oni / one / ona su – they are

So:

Brzina je problem = Speed is a problem.
Third person singular → je.

You might also see or hear jest in more formal or emphatic style, but je is the normal everyday form:

Brzina jest problem u prometu. (a bit more formal / emphatic)

Both brzina and problem are nouns. Why are they both in the same form? In some languages, the complement takes a different case.

In standard Croatian, with the verb biti (to be), both:

the subject and
the noun that describes / equals the subject (the predicate noun)

are in the nominative case.

So:

Brzina (NOM) je problem (NOM).
On (NOM) je učenik (NOM). – He is a student.
Ona (NOM) je učiteljica (NOM). – She is a teacher.

You will sometimes hear colloquial sentences with different cases in speech, but the correct, standard form with biti + noun is nominative–nominative, as in this sentence.

Can I change the word order, for example say Problem u prometu je brzina? Does the meaning change?

Yes, you can change the word order; the basic meaning stays the same, but emphasis shifts.

Possible variants:

Brzina je problem u prometu.
Neutral: Speed is a problem in traffic. (focus on speed as topic)
Problem u prometu je brzina.
Emphasis on problem u prometu: “As for the problem in traffic, it’s speed.”
U prometu je problem brzina.
Emphasis on u prometu (in traffic): “In traffic, the problem is speed.”

Croatian word order is fairly flexible, but:

Keep je close to the word it belongs with (usually right after the first stressed element).
Don’t break phrases like u prometu in unnatural ways.

The original Brzina je problem u prometu is the most neutral, textbook version.

If I want to add adjectives, how does agreement work? For example, “High speed is a big problem in traffic”?

Adjectives in Croatian agree in gender, number, and case with the noun they describe.

Nouns here:

brzina – feminine singular, nominative
problem – masculine singular, nominative

So, add adjectives:

visoka brzina – high speed (visoka feminine singular NOM)
velik problem – a big problem (velik masculine singular NOM)

Full sentence:

Visoka brzina je velik problem u prometu.
= High speed is a big problem in traffic.

You’ll also see veliki problem; with some masculine nouns both velik and veliki nominative forms appear in practice. The key point is that visoka must match brzina (feminine), and velik(i) must match problem (masculine).

Is there any difference between Croatian promet and Serbian saobraćaj for “traffic”?

Yes, this is mainly a regional / standard-language difference:

In standard Croatian, the usual word for traffic is promet.
- Brzina je problem u prometu. – Croatian standard.
In standard Serbian, the usual word is saobraćaj.
- Brzina je problem u saobraćaju. – Serbian standard.

Both are understood across the region, but promet sounds more Croatian, and saobraćaj more Serbian. The grammar around them (cases, prepositions) works the same way:

u prometu (Croatian)
u saobraćaju (Serbian)

In the Croatian sentence you’re learning, promet is the correct and natural choice.