Learn Hardcore Croatian: U ruksaku uvijek imam mali rječnik kako bih brzo našao prijevod nepoznate riječi. - In my backpack I always have a small dictionary so that I can quickly find the translation of an unknown word.

u + locative = location (where something is)
- u ruksaku = in the backpack (static location)
u + accusative = movement into somewhere (where something is going)
- u ruksak = into the backpack (movement)

In your sentence, the dictionary is already in the backpack, not moving into it, so Croatian uses the locative: u ruksaku.

Why is there no ja (I) in the sentence before imam?

In Croatian, subject pronouns (ja, ti, on, ona, etc.) are usually dropped if the subject is clear from the verb ending.

imam can only mean I have (1st person singular)
So ja imam and imam both mean I have, but imam is more natural in everyday speech.

You only add ja for emphasis or contrast, e.g.:

Ja uvijek imam mali rječnik… – I (as opposed to others) always have a small dictionary…

Where can uvijek go in the sentence? Is U ruksaku uvijek imam… the only correct word order?

Uvijek (always) is quite flexible in position. The version in your sentence:

U ruksaku uvijek imam mali rječnik…
is very natural and common.

Other acceptable options:

Uvijek u ruksaku imam mali rječnik… (slightly stronger emphasis on always)
U ruksaku imam uvijek mali rječnik… (a bit marked, but possible)

What you generally cannot do is put uvijek between the verb and its object in a way that sounds broken, e.g.
✗ Imam uvijek mali rječnik u ruksaku – not wrong, but sounds a bit clumsy; Croatian prefers adverbs earlier in the clause.

Your original order is among the most natural.

Why is it mali rječnik and not rječnik mali?

In Croatian, descriptive adjectives (like mali = small) usually come before the noun:

mali rječnik – a small dictionary
velika knjiga – a big book

Putting the adjective after the noun (rječnik mali) is unusual in modern standard Croatian and would sound poetic, playful, or old‑fashioned, not neutral.

Grammatically:

mali is masculine singular accusative, agreeing with rječnik (masculine singular accusative) as the direct object of imam.

What is the difference between rječnik and something like riječnik or rečnik?

Standard Croatian uses rječnik.

rječnik (Croatian standard) – dictionary; vocabulary
rečnik (Serbian, Ekavian) – used in Serbian, not standard Croatian
riječnik – sometimes seen historically or regionally, but rječnik is the standard form today

So in standard Croatian you should use rječnik.

What exactly does kako bih mean here, and how is it different from da bih or just da?

In this sentence, kako bih introduces a purpose clause:

kako bih brzo našao… ≈ so that I (would) quickly find… / in order to quickly find…

Nuances:

kako bih – a bit more formal/literary, very common in writing
da bih – also correct and common:
…imam mali rječnik da bih brzo našao…
da (without bih) – less explicit conditional; also common:
…imam mali rječnik da brzo nađem…

All three are understandable; kako bih and da bih clearly signal a desired result/purpose (so that I would…).

In everyday speech, many people would say:

U ruksaku uvijek imam mali rječnik da brzo nađem prijevod…

What is bih here? Why do we need it?

Bih is the conditional form of the verb biti (to be) for 1st person singular:

ja bih
ti bi
on/ona/ono bi
mi bismo
vi biste
oni/one/ona bi

Together with a past participle, it forms the Conditional I:

bih našao – I would find
bismo našli – we would find

In your sentence:

kako bih brzo našao ≈ so that I would quickly find

So bih is necessary here to show that this is a conditional/purpose meaning, not just a simple present.

Why is it našao and not nađem or naći?

The verb naći (to find) is used here in the conditional:

bih našao = I would find

That conditional is formed from:

bih (conditional of biti)
The past participle – here našao (masculine singular of naći)

So:

kako bih brzo našao = so that I would quickly find

If you used nađem (present tense):

…da brzo nađem prijevod… = so that I (can) quickly find the translation…
→ Also correct, just a different structure.

If you used the infinitive naći:

…imam mali rječnik da brzo naći prijevod… ✗ – incorrect in standard Croatian; you don’t use the bare infinitive after da this way.

So in your original form, našao must be a past participle because of the conditional bih.

Why is it našao and not našla or našlo?

The past participle našao agrees in gender and number with the subject.

našao – masculine singular
našla – feminine singular
našlo – neuter singular
našli – masculine/mixed plural
našle – feminine plural

In your sentence, the understood subject is ja (I), and we are assuming the speaker is male, so:

(muškarac) ja bih našao
(žena) ja bih našla

If a woman said the same sentence, she would say:

U ruksaku uvijek imam mali rječnik kako bih brzo našla prijevod nepoznate riječi.

Why is it prijevod nepoznate riječi and not something like prijevod nepoznata riječ?

Prijevod (translation) is a noun that very often takes a genitive to show “translation of something”:

prijevod nepoznate riječi = translation of an unknown word

So:

nepoznate riječi is in the genitive singular:
- base form: nepoznata riječ – unknown word
- genitive singular: nepoznate riječi – of an unknown word

Therefore, prijevod (čega?) nepoznate riječi
(čega? is the genitive question of what?).

Using nominative (nepoznata riječ) would be ungrammatical here.

Why does riječ become riječi in the genitive singular? It looks like a plural.

Riječ (word) is a feminine noun with an irregular pattern:

Nominative singular: riječ
Genitive singular: riječi
Nominative plural: riječi
Genitive plural: riječi (same form again)

So riječi can be:

genitive singular (of a word)
nominative plural (words)
genitive plural (of words)

In your sentence, the context tells us it’s genitive singular:

prijevod nepoznate riječi = translation of an unknown word
(of one word, not of unknown words).

Why is bih after kako and not after ja, like ja bih kako…?

Croatian has a strong rule about clitics (short, unstressed words like bih, bi, se, ga, je) that they usually go in second position in the clause.

In kako bih brzo našao…:

kako is the first word in the subordinate clause
bih is in second position (right after kako)

You cannot say:

✗ kako brzo bih našao… – this breaks the clitic rule
✗ ja bih kako brzo našao… – also unnatural in this structure

The correct and natural form is:

kako bih brzo našao…

Could we say da instead of kako bih, like …da brzo nađem prijevod…? Would the meaning change?

Yes, you can say:

U ruksaku uvijek imam mali rječnik da brzo nađem prijevod nepoznate riječi.

This is perfectly natural. The differences:

kako bih brzo našao – so that I would quickly find
→ slightly more formal/literary, uses the conditional.
da brzo nađem – so that I (can) quickly find
→ a bit more colloquial and direct, present tense rather than explicit conditional.

In practice, both express purpose. The nuance is small, and both are good Croatian.

Could we use nosim instead of imam, like U ruksaku uvijek nosim mali rječnik?

Yes, but there is a nuance.

imam = I have (I possess it; it is in my backpack)
nosim = I carry (I am carrying it / I usually carry it)

Your original:

U ruksaku uvijek imam mali rječnik…
emphasizes having it there whenever it’s needed.

Alternative:

U ruksaku uvijek nosim mali rječnik…
emphasizes the habit of carrying it around with you.

Both are grammatically correct; the choice depends on what you want to stress.