Learn Hardcore Croatian: On je pjesnik i piše kratke pjesme svaki dan. - He is a poet and writes short poems every day.

On piše kratke pjesme. = Piše kratke pjesme. (both mean He writes short poems.)
The verb form piše clearly indicates 3rd person singular, so on is not strictly necessary.

In this sentence, on is used:

to introduce or emphasize who we are talking about,
or to contrast with someone else (e.g. On je pjesnik, a ona je slikarica. – He is a poet, and she is a painter.)

So:

Grammatically, on can be omitted.
Pragmatically, it’s used here for clarity or emphasis.

What exactly is je and why is it in the second position?

Je is the 3rd person singular present tense of biti (to be):

(ja) sam
(ti) si
(on/ona/ono) je
(mi) smo
(vi) ste
(oni/one/ona) su

It is also a clitic (an unstressed, short word) that usually stands in second position in the sentence or clause.

In On je pjesnik, the order is:

On (first stressed word)
je (clitic – second position)
pjesnik (predicate noun)

You normally cannot put je at the end:
✗ On pjesnik je – incorrect in standard Croatian.

Why is there no word like a or the before pjesnik? How do you say a poet vs the poet?

Croatian has no articles like English a / an / the.
Pjesnik by itself can mean a poet or the poet, depending on context.

On je pjesnik.
- usually: He is a poet. (introducing what he does)
To je onaj pjesnik. – That is the poet.
Pjesnik kojeg poznaješ… – The poet whom you know…

Definiteness (a/the) is expressed through:

context,
word order,
additional words (e.g. taj, onaj, ovaj = that/this).

You do not normally say On je jedan pjesnik for He is a poet; jedan here sounds like one (particular) poet and often adds a nuance like just one of many or some poet.

What form and gender is pjesnik? Does the ending -ik mean it’s masculine?

Pjesnik is:

masculine gender
singular
nominative case

The ending -ik is very common for masculine nouns, especially for professions and roles:

učenik – pupil
radnik – worker
vozač (not -ik but also masc) – driver
glazbenik – musician

The most basic dictionary form of a noun is nominative singular, so you will see it listed as pjesnik.

Feminine for pjesnik is usually pjesnikinja (poetess / female poet).

What does i mean, and why isn’t there a comma before it like in English?

I means and.

On je pjesnik i piše kratke pjesme svaki dan.
= He is a poet and (he) writes short poems every day.

Regarding commas:

In English you might write: He is a poet, and he writes…
In Croatian, you normally do not use a comma before i when simply joining two parts with the same subject:
- On je pjesnik i piše kratke pjesme. – no comma
- You would use a comma with i in more complex structures, but not in a basic sentence like this.

So the lack of a comma before i is standard Croatian punctuation.

What is the verb piše? What is its infinitive and which tense is this?

Piše is:

3rd person singular
present tense
of the verb pisati – to write

Conjugation in the present (singular):

(ja) pišem – I write
(ti) pišeš – you write
(on/ona/ono) piše – he/she/it writes

The present tense in Croatian is used:

for actions happening now,
and for habitual/repeated actions, like in this sentence (he writes short poems every day).

Why is piše (imperfective) used here instead of a perfective form? Is aspect important?

Yes, aspect is very important in Croatian.

Pisati – imperfective (ongoing, repeated, habitual)
Napisati – perfective (completed action)

In On je pjesnik i piše kratke pjesme svaki dan:

piše (imperfective) expresses a habitual action – something he does regularly.
Using the perfective napiše would suggest something like he manages to write / finishes writing short poems every day (focus on completion each day), which sounds different and more result‑oriented.

For a simple “he writes … every day”, the imperfective piše is the natural choice.

What case are kratke pjesme, and why do the endings look like that?

Kratke pjesme is in the accusative plural, because it’s the direct object of the verb piše.

pjesma – poem / song (feminine)
Nominative singular: pjesma
Accusative singular: pjesmu
Nominative plural: pjesme
Accusative plural: pjesme (same form as nominative plural)

The adjective kratke agrees with the noun:

feminine
plural
accusative

So:

kratka pjesma – a short poem (nom. sg.)
kratku pjesmu – a short poem (acc. sg.)
kratke pjesme – short poems (nom. or acc. pl., here: acc. pl.)

Why does the adjective kratke come before pjesme? Can it come after the noun?

In Croatian, the default word order is:

adjective + noun

So:

kratke pjesme – short poems
dobre knjige – good books
stari prijatelj – old friend

You can sometimes put the adjective after the noun, but:

it is less common in everyday speech,
usually sounds more poetic, literary, or emphatic,
or appears in fixed expressions.

So pjesme kratke could be used in a stylistic/poetic context, but for neutral everyday language kratke pjesme is the normal, natural order.

What does svaki dan mean exactly, and how is it formed?

Svaki dan means every day.

svaki – every (masculine singular, nominative/accusative)
dan – day (masculine noun)

Together, svaki dan is an adverbial time expression:

It answers when? – When does he write? → svaki dan.

Morphologically:

svaki agrees with dan in gender (masc.), number (sg.), and case (here: accusative used as a time expression).

What is the difference between svaki dan and svakog dana?

Both can mean every day, but there is a slight grammatical difference:

svaki dan – accusative
svakog dana – genitive

In time expressions:

accusative often indicates duration or a repeated time point:
Piše kratke pjesme svaki dan. – He writes short poems every day.
genitive is also common with time expressions and often sounds a bit more formal or literary:
Piše kratke pjesme svakog dana.

In practice:

Both are correct and very common.
In casual speech, svaki dan might be slightly more neutral/frequent.
You can treat them as near‑synonyms in this context.

Can the word order with svaki dan change? For example, can I say Svaki dan on piše kratke pjesme?

Yes, Croatian word order is flexible, and moving svaki dan changes emphasis, not basic meaning.

All of these are grammatical:

On je pjesnik i piše kratke pjesme svaki dan.
– neutral; time at the end.
On je pjesnik i svaki dan piše kratke pjesme.
– emphasizes the regularity (every day).
Svaki dan on piše kratke pjesme.
– stronger emphasis on every day, and a bit on on (he, as opposed to someone else).
On svaki dan piše kratke pjesme.
– also emphasizes the habit.

So yes, you can move svaki dan, but be aware that Croatian speakers use word order to highlight different parts of the message.

Does pjesma mean both poem and song? How do I know which one is meant?

Yes, pjesma can mean poem or song, depending on context.

Pisati pjesme – can be:
- to write poems (as a poet),
- to write songs (as a songwriter/lyricist).
pjevati pjesme – to sing songs (here it clearly means songs).

In On je pjesnik i piše kratke pjesme svaki dan, because he is a pjesnik (poet), pjesme will normally be understood as poems.
If you needed to be explicit about songs, you could say something like:

On je kantautor i piše pjesme svaki dan. – He is a singer‑songwriter and writes songs every day.