Learn Hardcore Croatian: On čuva svoje knjige u sobi.

svoj = one’s own (reflexive possessive; refers back to the subject)
njegov / njegova / njegovo = his (general possessive; can refer to some male person, not necessarily the subject)

Because the subject On (he) is also the owner of the books, the normal, neutral choice is the reflexive possessive svoje:

On čuva svoje knjige. = He keeps his own books.
On čuva njegove knjige. ≈ He keeps his books (someone else’s, some other man’s books).

So svoje knjige tells us the books belong to him, the subject of the sentence.

What exactly does čuva mean here? Is it just “keeps”?

The verb is čuvati (infinitive). Čuva is 3rd person singular: he keeps / he guards / he looks after.

Its basic meanings:

guard, protect: Čuva djecu. – He looks after / watches the children.
keep, store: Čuva dokumente u ladici. – He keeps the documents in a drawer.
preserve: Čuva tradiciju. – He preserves the tradition.

In On čuva svoje knjige u sobi, čuva suggests more than just physically having the books. It implies he keeps them carefully or stores them (perhaps with some sense of protecting them). If you just mean “He has his books in the room”, you might also use ima (has) or drži (keeps/holds):

On drži svoje knjige u sobi. – He keeps his books in the room (more neutral, less “protective” nuance).

What case is knjige, and why does it end in -e?

The noun is knjiga (book), a feminine noun.

In the sentence, knjige is in the accusative plural because it is the direct object of the verb čuva.

Declension of knjiga (singular → plural):

Nominative: knjiga → knjige
Accusative: knjigu → knjige

So for feminine nouns like knjiga, the nominative plural and accusative plural often look the same (knjige). Here you know it’s accusative because it’s what he is keeping/guarding.

Why is it u sobi and not u sobu?

The preposition u can take two cases:

Accusative = motion into something (where to?)
- Idem u sobu. – I’m going into the room.
Locative = location in something (where?)
- On je u sobi. – He is in the room.

In On čuva svoje knjige u sobi, the idea is where he keeps the books (location), not motion into somewhere. So u + locative is used:

u sobi = in the room (locative)
u sobu = into the room (accusative, motion)

What case is sobi, and why does it end in -i?

The noun is soba (room), a regular feminine noun.

In the phrase u sobi, sobi is:

Locative singular of soba

Basic singular forms of soba:

Nominative: soba (room)
Genitive: sobe (of the room)
Dative: sobi (to/for the room)
Accusative: sobu
Locative: sobi (in the room)
Instrumental: sobom (with the room)

So u sobi = in (the) room, using the locative singular ending -i.

Can the subject On be dropped in Croatian?

Yes. Croatian is a pro‑drop language: the subject pronoun is often omitted because the verb ending already shows the person and number.

On čuva svoje knjige u sobi. – He keeps his books in the room.
Čuva svoje knjige u sobi. – (He) keeps his books in the room.

You usually omit On unless:

you want to emphasize he (as opposed to someone else),
or you need to clarify who is meant in a confusing context.

Otherwise, Čuva svoje knjige u sobi. is completely natural.

How does word order work here? Can I say On u sobi čuva svoje knjige or Svoje knjige čuva u sobi?

Croatian word order is relatively flexible. All of these can be correct, but the emphasis shifts:

On čuva svoje knjige u sobi.
Neutral: focus on the whole statement.
On u sobi čuva svoje knjige.
Slight emphasis on u sobi: it’s in the room that he keeps them (maybe not elsewhere).
Svoje knjige čuva u sobi.
Emphasis on svoje knjige (“His own books he keeps in the room”), perhaps contrasting with other things he keeps elsewhere.
U sobi čuva svoje knjige.
Emphasis on u sobi first: “In the room he keeps his books”, setting the place as the topic.

Grammatically, as long as you keep connected words together (e.g. svoje knjige together, u sobi together), word order is mainly about information structure and emphasis, not about correctness.

What is the infinitive of čuva and how is it conjugated in the present tense?

The infinitive is čuvati (to keep, guard, look after).

Present tense (imperfective):

ja čuvam – I keep
ti čuvaš – you keep (sg, informal)
on/ona/ono čuva – he/she/it keeps
mi čuvamo – we keep
vi čuvate – you keep (pl or formal)
oni/one/ona čuvaju – they keep

In On čuva svoje knjige u sobi, čuva is 3rd person singular, matching On.

Why does svoje look like an adjective? Does it agree with knjige?

Yes. Svoj is a reflexive possessive adjective. Like adjectives, it agrees with the noun in:

gender
number
case

Here the noun is knjige:

feminine
plural
accusative

So svoj takes the form svoje to match:

svoje knjige = his own books (fem, plural, accusative)

Other examples:

svoja knjiga – his/her own book (fem, sg, nom)
svog brata – his/her own brother (masc, sg, acc/gen)
svojim prijateljima – to his/her own friends (dat/ins, pl)

So yes, svoje behaves grammatically like an adjective attached to knjige.

How would I say his books if the books are not his own, but belong to another man?

Then you use njegov (non‑reflexive possessive), not svoj.

Examples:

On čuva njegove knjige u sobi.
He keeps his books in the room – i.e. the books of some other man previously mentioned.
Marko čuva njegove knjige.
Marko keeps his (another man’s) books.

If the books belong to the subject himself:

On čuva svoje knjige. – He keeps his own books.

How do you express “the room” vs “a room” in Croatian, since there are no articles?

Croatian has no articles (no “a/an” or “the”). The noun soba or sobi can mean either a room or the room, depending on context.

On čuva svoje knjige u sobi.
Could be translated as:
- He keeps his books in a room, or
- He keeps his books in the room.

Context usually makes the meaning clear. If you really need to specify, you can add words:

u jednoj sobi – in one room / in a room
u toj sobi – in that room (sounds like “in the room” already known in context)

How are the consonants pronounced in čuva, knjige, and sobi?

Key points:

č = like English ch in church
- čuva ≈ CHOO‑va
j = like y in yes
- knjige ≈ KNYI‑geh (k + palatalized n + y‑sound)
knj together: say k, then a palatal n (like Spanish ñ), then y.
g in knjige is always a hard g as in go, never like English “j” in giant.
s in sobi is always like s in see, never like English “z” in “rose”.

There is no silent letter here; everything written is pronounced.

Where do possessive adjectives usually go in Croatian – before or after the noun?

They usually go before the noun:

moja knjiga – my book
tvoja soba – your room
njegove knjige – his books
svoje knjige – his/her own books

Putting them after the noun is possible but marked, for stylistic or emphatic reasons, and sounds unusual in everyday speech. For learning and normal usage, keep possessives before the noun, as in svoje knjige.