Learn Hardcore Croatian: On stalno uči hrvatski navečer. - He constantly learns Croatian in the evening.

On stalno uči hrvatski navečer. – fully explicit, often used:
- when you contrast him with someone else: On stalno uči, a ona gleda TV.
- for emphasis on he (as opposed to others).
Stalno uči hrvatski navečer. – completely natural in neutral context; this is what you’d hear most often in conversation.

So: On is optional here, not required for grammar.

Why is it uči and not something like uči se or uči hrvatski jezik?

The verb is učiti (to learn / to study).

Without "se"
- učiti nešto = to learn/study something
- učiti se exists, but it usually means “to be learning” in a more general or reflexive way, and it’s less common in the sense “study a subject”.
- For languages, the normal pattern is:
  - učiti engleski / hrvatski / njemački (no se).
With or without jezik
- učiti hrvatski and učiti hrvatski jezik both mean “to learn Croatian (language)”.
- hrvatski jezik is slightly more formal or explicit.
- In everyday speech, people almost always drop jezik and just say hrvatski.

So On stalno uči hrvatski navečer is the most natural everyday version.

Why is hrvatski in that form? Shouldn’t the adjective change in the accusative case?

Hrvatski here is grammatically an adjective used as a noun, meaning “Croatian (language)”.

Base form (nominative m. sg.): hrvatski
Accusative m. sg., inanimate: same form as nominative → hrvatski

So in:

On uči hrvatski. – he is learning Croatian
hrvatski is masculine, singular, inanimate, accusative, but it looks the same as the nominative. That’s why you don’t see any change.

If you expanded it:

On uči hrvatski jezik.
- hrvatski = adjective, masculine accusative
- jezik = masculine accusative noun

Again, both hrvatski and hrvatski jezik are correct.

What is the difference between stalno, uvijek, and često?

All three relate to frequency, but with different nuances:

stalno = constantly, all the time; often carries a hint of annoyance or exaggeration
- On stalno uči hrvatski navečer.
  → “He is constantly studying Croatian in the evenings.” (could sound like a complaint)
uvijek = always (more neutral, factual)
- On uvijek uči hrvatski navečer.
  → “He always studies Croatian in the evenings.”
često = often
- On često uči hrvatski navečer.
  → “He often studies Croatian in the evenings.”

So stalno can feel a bit emotionally loaded in many contexts.

Why is it navečer and not u večer or po večeri? What’s the difference?

All of these relate to “evening”, but they’re not used the same way:

navečer – a fixed adverb meaning in the evening / in the evenings
- Most common in everyday speech for this meaning.
- On uči hrvatski navečer.
u večer – grammatically possible but unusual in modern speech; sounds archaic or poetic.
u večernjim satima – formal: “in the evening hours”.
svake večeri / svaku večer – “every evening”.
večerom – slightly old-fashioned/poetic instrumental form, “in the evenings”.

For everyday modern Croatian, navečer is what you normally use.

Can the word order change? For example, is On navečer stalno uči hrvatski also correct, and does it change the meaning?

Yes, Croatian word order is quite flexible, and several versions are correct. The basic meaning stays the same, but the focus or rhythm can change.

All of these are grammatically possible:

On stalno uči hrvatski navečer.
Neutral English: “He constantly studies Croatian in the evening.”
On navečer stalno uči hrvatski.
Slightly more emphasis on in the evening.
Navečer on stalno uči hrvatski.
Stronger emphasis on navečer (as a contrast: “In the evening, he’s always studying Croatian.”).
On hrvatski stalno uči navečer.
Possible but sounds a bit marked; focus falls heavily on hrvatski.

The “safest” neutral patterns for a learner are:

On stalno navečer uči hrvatski.
On stalno uči hrvatski navečer.
On navečer uči hrvatski. (if you drop stalno)

Does uči mean “he learns” or “he is learning”? How do I say the English present continuous?

Croatian present tense covers both English simple present and present continuous. So:

On uči hrvatski.
can mean:
- “He learns Croatian (in general).”
- “He is learning Croatian (right now / these days).”

If you want to make the ongoing meaning clearer, you usually add time expressions:

On ovih dana uči hrvatski. – He is learning Croatian these days.
On sada uči hrvatski. – He is learning Croatian now.

In your sentence, On stalno uči hrvatski navečer, the idea is closer to
→ “He is always studying Croatian in the evenings.”

What is the difference between učiti and naučiti?

These two verbs differ in aspect:

učiti – imperfective, focuses on the process:
- On uči hrvatski. – He is studying/learning Croatian.
naučiti – perfective, focuses on the result / completion:
- On je naučio hrvatski. – He has learned Croatian (he knows it now).

So:

Use učiti when you talk about someone studying.
Use naučiti when you talk about someone having finished learning it successfully.

How would I say the same thing about a woman instead of a man?

You only need to change the pronoun; the verb and the rest of the sentence stay the same:

On stalno uči hrvatski navečer. – He constantly studies Croatian in the evening.
Ona stalno uči hrvatski navečer. – She constantly studies Croatian in the evening.

The verb uči doesn’t change for gender in the present tense.

How would I make this sentence negative, for example “He doesn’t constantly study Croatian in the evening”?

Negation of verbs in Croatian uses ne before the verb:

On ne uči hrvatski navečer. – He doesn’t study Croatian in the evening.
On stalno ne uči hrvatski navečer. – ungrammatical / strange; you can’t just stick ne in the middle like that.

To express “not always / not constantly”, you change the adverb:

On ne uči uvijek hrvatski navečer.
– He doesn’t always study Croatian in the evening.
On ne uči stalno hrvatski navečer.
– He doesn’t constantly study Croatian in the evening.

So: ne goes directly in front of uči, and you might adjust stalno / uvijek / često to match your meaning.