Learn Hardcore Croatian: Ponašaš se kao da je svaka pogreška velik problem, ali učenje jezika ne ide na taj način. - You behave as if every mistake were a big problem, but language learning does not work that way.

ponašati by itself is not normally used in the sense of behave.
The dictionary form you will see is ponašati se.
In the present tense:
- (ja) se ponašam
- (ti) se ponašaš
- (on/ona/ono) se ponaša
- etc.

So Ponašaš se… literally = You are behaving…
Saying Ponašaš kao da… sounds wrong/unfinished to a native speaker.

What exactly does kao da mean, and how is it different from just kao?

kao on its own = like / as (for simple comparisons):
- Ponašaš se kao dijete. = You behave like a child.
kao da = as if / as though, and is followed by a full clause (with a verb):
- Ponašaš se kao da je svaka pogreška velik problem.
  = You behave as if every mistake is a big problem.

So kao + noun/adjective; kao da + clause.

Why is it kao da je svaka pogreška velik problem, not something like kao da bi svaka pogreška bila velik problem?

Croatian has two common options after kao da:

Indicative (realistic / neutral comparison)
- Ponašaš se kao da je svaka pogreška velik problem.
  Literally: You behave as if every mistake *is a big problem.*
  This is the normal, neutral wording here.
Conditional (unreal / clearly imaginary comparison)
- Ponašaš se kao da bi svaka pogreška bila velik problem.
  Literally: You behave as if every mistake *would be a big problem.*

Both are grammatically correct.
With je, the speaker just describes your behavior.
With bi bila, the speaker stresses that this idea is unreal or exaggerated. In everyday speech, the je version is more common in this kind of sentence.

Why is the order je svaka pogreška velik problem? Could I say svaka pogreška je velik problem instead?

Yes, you can say Svaka pogreška je velik problem. That would be the most neutral word order if the sentence started there.

In your sentence, je svaka pogreška velik problem comes after kao da, and Croatian allows some flexibility in word order to adjust emphasis and rhythm.

kao da je svaka pogreška velik problem (original)
Slight emphasis on svaka pogreška as the subject of the clause.
kao da svaka pogreška je velik problem
Grammatically possible, but sounds less natural here.

The key point: both je svaka pogreška velik problem and svaka pogreška je velik problem are acceptable; natives rearrange elements for flow and focus more freely than in English.

What cases are svaka pogreška and velik problem in, and why?

svaka pogreška is in the nominative singular (feminine):
- svaka = each/every (feminine nominative singular)
- pogreška = mistake (feminine nominative singular)
velik problem is also nominative singular (masculine):
- velik = big (masculine nominative singular, short form)
- problem = problem (masculine nominative singular)

This is a linking structure with the verb biti (je):

svaka pogreška (subject) + je + velik problem (predicative noun phrase)

Both sides of je are in the nominative because they refer to the same thing: every mistake = a big problem.

Why is it velik problem and not veliki problem?

Both velik problem and veliki problem are grammatically correct. The difference is:

velik – short form adjective
veliki – long form adjective

In modern standard Croatian, with many concrete nouns like problem, both forms are acceptable and the meaning difference is small or none in everyday speech.

Very roughly:

Short forms (velik, malen, etc.) often sound a bit more neutral or are used in set phrases.
Long forms (veliki, mali) can sound slightly more “full” or emphatic, and often appear in attributive position before a noun:
- veliki problem – a big problem

In predicative position (after je), natives often use short forms:

To je velik problem.
But To je veliki problem. is also fine.

What is the difference between pogreška and greška?

Both mean mistake / error.

pogreška – more standard, often preferred in formal writing.
greška – very common in everyday speech; also accepted.

There is no big meaning difference in this context.
You could say:

svaka pogreška
svaka greška

Both would be understood as every mistake.

Why is it učenje jezika, not učenje jezik?

učenje is a verbal noun meaning learning / studying (from učiti).

When a verb takes an object in the accusative (e.g. učiti jezik – to learn a language), its verbal noun usually takes that object in the genitive:

Verb: učiti jezik (accusative) – to learn a language
Noun: učenje jezika (genitive) – learning (of) a language

So:

učenje = learning
jezika = of (a/the) language (genitive singular)

učenje jezik is ungrammatical; the object of učenje must be in the genitive case.

Why is there no word for a or the in učenje jezika? Shouldn’t it be “a language” or “the language”?

Croatian has no articles like English a/an or the.

jezik can mean a language or the language, depending on context.
jezika (genitive) likewise can mean of a language, of the language, or of languages, depending on context.

In učenje jezika, the context clearly suggests learning a language (in general). Croatian relies on context and word order, not on articles, to express this kind of nuance.

What does učenje jezika ne ide na taj način literally mean, and why use ići (“to go”) here?

Literal components:

učenje jezika – learning (of) language
ne ide – does not go
na taj način – in that way / in that manner

Literal translation: “Language learning does not go in that way.”

But ići (to go) is often used idiomatically in Croatian with the meaning:

to proceed, to work, to function, to happen

So ne ide here means doesn’t work / doesn’t happen / doesn’t go like that.
A natural English translation is:

That’s not how language learning works.
Language learning doesn’t work that way.

Why is it na taj način and not u taj način?

With način (way, manner), Croatian normally uses na, not u:

na ovaj način – in this way
na onaj način – in that way
na neki način – in some way
na pogrešan način – in the wrong way

So na taj način is the standard fixed combination: in that way / like that.
u taj način would sound wrong to a native speaker.

Is ponašaš se closer to “you behave” or “you are behaving” in English?

It can correspond to both.

Croatian present tense covers:

general habits:
- Ponašaš se kao dijete. = You behave like a child.
current/temporary behavior:
- Zašto se sada tako ponašaš? = Why are you behaving like that now?

In your sentence, English would probably use the progressive:

You’re acting / You’re behaving as if every mistake is a big problem…

But grammatically it’s just the simple present in Croatian.

Could I replace ali with something else like no or međutim?

Yes, but with slight stylistic differences:

ali – the most common word for but, neutral and used everywhere.
no – also but, a bit more literary or formal in some uses, and sometimes a bit stronger contrast.
međutim – however, typically starts a new sentence or clause and sounds more formal/written.

In your sentence:

…, ali učenje jezika ne ide na taj način. – perfectly natural, neutral.
…, no učenje jezika ne ide na taj način. – also correct; slightly more formal/literary tone.
… Međutim, učenje jezika ne ide na taj način. – usually with a full stop before and capital M; more like However, … in written style.