Learn Hardcore Croatian: Nikad ne kasnim u školu.

Croatian requires negative concord: a negative word like nikad (never) must be accompanied by the negative particle ne before the verb. This is normal and not “double negative” in the English sense.

Correct: Nikad ne kasnim.
Also: Nitko ne dolazi (Nobody is coming), Ništa ne razumijem (I don’t understand anything). Leaving out ne with nikad in a full sentence is ungrammatical.

Can I replace nikad with nikada? Does it change the meaning?

Yes. Nikad and nikada mean the same thing. Nikada can feel a bit more emphatic or formal, but both are fully standard:

Nikad ne kasnim u školu.
Nikada ne kasnim u školu.

Can I drop ne and say Nikad kasnim u školu?

No. With nikad, the verb must be negated with ne: Nikad ne kasnim u školu.
Exception: in very short answers you can say just Nikad! (Never!), but that’s not a full sentence.

Where should nikad go in the sentence?

Typical placements:

At the start: Nikad ne kasnim u školu. (neutral and common)
Before the verb inside the clause: Ja nikad ne kasnim u školu. You cannot move ne away from the verb; it must stay immediately before it: ne kasnim.

Do I need to say ja?

No. The verb ending already encodes the subject. Kasnim means “I am late.”
Add ja only for emphasis or contrast:

Neutral: Nikad ne kasnim u školu.
Emphatic: Ja nikad ne kasnim u školu.

Why is it u školu and not u školi?

Because u with the accusative (u školu) expresses motion or destination, matching the idea “late to school.”
Use the locative (u školi) for location “at/in school.”

Going/arriving: Idem u školu. Kasnim u školu.
Being there: Ja sam u školi.

Why not na školu?

With škola, Croatian uses u for both “to school” (u školu) and “at school” (u školi). Na školu is not used in this sense.
However, other nouns do take na:

To work: na posao; at work: na poslu
To university: very commonly na fakultet; at university: na fakultetu
To an event: na koncert, na sastanak

What case is školu, and why?

Školu is accusative singular of the feminine noun škola. It’s required by the preposition u when expressing motion toward a place. Mini-paradigm:

Nominative: škola
Genitive: škole
Dative: školi
Accusative: školu
Locative: školi
Instrumental: školom

How do I conjugate kasniti?

Kasniti means “to be late.” Present tense:

ja kasnim
ti kasniš
on/ona/ono kasni
mi kasnimo
vi kasnite
oni/one/ona kasne It’s imperfective, so it’s good for habits and ongoing situations.

What’s the difference between kasniti and zakasniti?

Kasniti (imperfective): being late as an ongoing or habitual situation. Example: Nikad ne kasnim u školu.
Zakasniti (perfective): to end up late on a particular occasion. Example: Jučer sam zakasnio/zakasnila u školu.

How do I say “I’ve never been late for school”?

Use the perfective in the past:

Male speaker: Nikad nisam zakasnio u školu.
Female speaker: Nikad nisam zakasnila u školu. Using nikada is equally fine: Nikada nisam zakasnio/zakasnila u školu.
You may also hear the imperfective past (nisam kasnio/la), but perfective zakasniti is more natural for “ever/never” experiences.

Can I omit u školu?

Yes. Nikad ne kasnim is a general statement “I’m never late.” Add u školu only if you want to specify the destination or context.

Why not use za to translate “late for school,” like kasnim za školu?

Because za is not used with kasniti to mean “late for” a destination or event. Use:

kasniti u
- accusative for enclosed places: kasnim u školu, kasnim u razred
kasniti na
- accusative for events/meetings/transport: kasnim na sastanak, kasnim na autobus So, not kasnim za školu.

How do I ask “Do you ever come late to school?” in Croatian?

Use ikad (ever), not nikad:

Neutral present: Kasniš li ikad u školu?
For a life experience: Jesi li ikad zakasnio u školu? (male) / Jesi li ikad zakasnila u školu? (female)

Is a comma needed after initial Nikad?

No. Nikad ne kasnim u školu. needs no comma. A comma would only appear with a special intonational pause or in more complex sentences.

Any pronunciation tips for this sentence?

š is like English “sh” in “ship”: školu sounds like “shkoh-loo.”
u is always “oo” as in “food.”
ne is a short, unstressed particle before the verb: ne kasnim flows together.