Learn Hardcore Croatian: Svaki dan stavljam knjige u ruksak. - Every day I put books in the backpack.

Croatian is a pro‑drop language: subject pronouns (ja = I, ti = you, etc.) are usually omitted because the verb ending already tells you who the subject is.

stavljam is the 1st person singular present tense form of stavljati (to put, to place regularly).
That ending ‑am clearly shows the subject is I.

So Svaki dan stavljam knjige u ruksak. literally is Every day put‑I books into backpack, which naturally translates as Every day I put books in (my) backpack.

You could say Ja svaki dan stavljam knjige u ruksak, but that is only used when you want to emphasize I (and not someone else).

What is the difference between svaki dan and svakog dana?

Both svaki dan and svakog dana can mean every day, but they are slightly different grammatically:

svaki dan = every day (basic, neutral form)
- svaki = every (masculine, nominative)
- dan = day (masculine, nominative)
svakog dana = also every day, but literally of every day
- svakog = every (masculine, genitive)
- dana = of day (masculine, genitive)

In everyday speech:

Svaki dan stavljam knjige u ruksak. – very common and completely correct.
Svakog dana stavljam knjige u ruksak. – also correct; often sounds a bit more formal or stylistically elevated.

For a beginner, you can safely use svaki dan in most situations.

What does stavljam mean exactly, and what is its infinitive form?

stavljam is:

the 1st person singular, present tense form
of the verb stavljati (to put, to place, to be in the process of putting).

So:

stavljati = to be putting, to put repeatedly / habitually (imperfective aspect).
stavljam = I put / I am putting (now or habitually).

Example conjugation (present tense of stavljati):

ja stavljam – I put
ti stavljaš – you put (singular)
on/ona/ono stavlja – he/she/it puts
mi stavljamo – we put
vi stavljate – you put (plural or formal)
oni/one/ona stavljaju – they put

You might also see staviti (perfective aspect), which is more like to put once, to place (and finish the action):

Stavit ću knjige u ruksak. – I will put the books in the backpack (one specific action).

In your sentence expressing a repeated habit (every day), the imperfective stavljam is the natural choice.

Why is knjige used here and not knjiga?

knjiga means book (singular, nominative form). knjige here is:

plural (books)
in the accusative case (direct object of the verb).

In Croatian, the direct object of most verbs (what you put, read, see, etc.) is in the accusative.

Feminine noun knjiga declines like this (relevant forms):

Nominative singular (who/what?): knjiga – a book
Accusative singular (whom/what?): knjigu – a book (object)
Nominative plural: knjige – books
Accusative plural: knjige – books

So stavljam knjige = I put books.

If you wanted just one book:

Svaki dan stavljam knjigu u ruksak. – Every day I put a book in the backpack.

Why is it u ruksak and not u ruksaku?

The preposition u (in/into) can take either:

Accusative: movement into somewhere
Locative: location in somewhere (no movement)

In your sentence, there is movement into the backpack:

u ruksak = into the backpack (accusative: ruksak → ruksak)
u ruksaku = in the backpack (locative: ruksak → ruksaku)

Compare:

Stavljam knjige u ruksak. – I am putting the books into the backpack.
Knjige su u ruksaku. – The books are in the backpack.

So u + accusative = direction / movement, u + locative = location / where something already is.

Why don’t we say u mom ruksaku or u moj ruksak like in English in my backpack?

Croatian often omits possessive adjectives (my, your, his, etc.) when the owner is obvious from context, especially with:

body parts
family members
personal items like phone, bag, house, etc., when clearly referring to the speaker’s own.

Here, because I am the one putting books into a backpack, it is naturally understood that the backpack is mine.

Svaki dan stavljam knjige u ruksak. – Every day I put books in my backpack.

You can say:

Svaki dan stavljam knjige u moj ruksak.
Svaki dan stavljam knjige u svoj ruksak.

Both mean my backpack, but they’re usually only used when you want to emphasize my own, as opposed to someone else’s.

Can the word order be different, for example Knjige svaki dan stavljam u ruksak?

Yes. Croatian allows quite flexible word order because meaning is largely carried by endings (cases, verb forms), not position.

All of these are grammatically possible, with slight differences in emphasis:

Svaki dan stavljam knjige u ruksak.
Neutral, typical order. Focus on the habit (every day).
Knjige svaki dan stavljam u ruksak.
Emphasizes knjige (the books – as opposed to something else).
U ruksak svaki dan stavljam knjige.
Emphasizes into the backpack (as opposed to some other place).
Knjige stavljam u ruksak svaki dan.
Neutral, but with svaki dan moved to the end; often used in speech for rhythm.

For learners, the safest and most natural is the original:
Svaki dan stavljam knjige u ruksak.

Can I use the present tense in Croatian for habits the same way as in English?

Yes. The Croatian present tense of an imperfective verb (like stavljati) is used for:

Habits / routines
- Svaki dan stavljam knjige u ruksak. – Every day I put books in my backpack.
General truths / regular actions
- On uvijek nosi ruksak. – He always carries a backpack.
Actions happening now (if the context makes it clear)
- Stavljam knjige u ruksak. – I am putting books in the backpack (right now).

So using stavljam with svaki dan is a very natural way to express a repeated daily action.

What are the genders of knjiga and ruksak, and how does that affect the forms here?

knjiga is feminine
ruksak is masculine

Gender affects their endings:

knjiga (feminine):

Nominative singular: knjiga – a book
Accusative plural: knjige – books

ruksak (masculine, hard‑stem):

Nominative singular: ruksak – backpack
Accusative singular (for an inanimate masculine noun, same as nominative): ruksak
Locative singular: ruksaku

That’s why we see:

knjige (feminine accusative plural) as the direct object
u ruksak (masculine accusative singular) after u indicating movement into something

How are svaki, dan, knjige, and ruksak pronounced? Any tricky sounds?

Approximate pronunciation:

svaki – [SVA‑kee]
- sv together: like sv in svelte.
- a is always like a in father.
- ki like kee in key.
dan – [DAHN]
- again, a like in father, never like in day.
knjige – [KNYI‑geh]
- knj is a bit tricky: nj is a single sound (like Spanish ñ in niño, or ny in canyon).
- So knj is similar to kny said quickly.
- ge like ghe in get (hard g, not j).
ruksak – [ROOK‑sahk]
- u like oo in book (but shorter and pure).
- Final k is clearly pronounced; Croatian doesn’t devoice vowels, only consonants, and final consonants remain clear.

Stress patterns can vary regionally, but for understanding and being understood, the main challenge is pronouncing nj in knjige and the pure vowel sounds (no English‑style diphthongs).

How would this sentence change if I wanted to say Yesterday I put the books in the backpack instead of Every day I put books in the backpack?

You would change:

svaki dan (every day) → jučer (yesterday)
Use a perfective verb and a past tense form to mark a completed action in the past.

A natural version:

Jučer sam stavio knjige u ruksak. – if the speaker is male
Jučer sam stavila knjige u ruksak. – if the speaker is female

Notes:

The verb changes from stavljam (imperfective) to stavio / stavila (perfective past tense of staviti) to show a single completed past action, not a habit.
The structure sam stavio / sam stavila is the standard way to form the perfect tense in Croatian (using the auxiliary biti = to be
- past participle).