Humus zadržava vodu u posudi.

Because vodu is the accusative singular form of voda.

In this sentence, voda is the direct object of the verb zadržava (retains / holds), and direct objects usually go in the accusative in Croatian.

• voda = nominative singular
• vodu = accusative singular

So:

• Voda je hladna. = The water is cold.
• Humus zadržava vodu. = Humus retains water.

Because u can take different cases depending on meaning:

• u + locative = in / inside a place, with no movement
• u + accusative = into a place, showing movement

Here, u posudi means in the container, so it describes location, not motion. That is why Croatian uses the locative.

• u posudi = in the container
• u posudu = into the container

Compare:

• Voda je u posudi. = The water is in the container.
• Stavljam vodu u posudu. = I am putting water into the container.

Posudi is the locative singular of posuda.

The noun posuda is feminine, and after u meaning in, Croatian uses the locative.

A very simplified pattern is:

• posuda = nominative singular
• posudi = locative singular

So u posudi literally means in a container / in the container.

Because humus is in the nominative form, and it matches the verb as the thing doing the action.

In this sentence:

• Humus = subject
• zadržava = verb
• vodu = object
• u posudi = prepositional phrase

Even though Croatian word order is flexible, the case endings help you identify the roles:

• humus = nominative subject
• vodu = accusative object

So humus is the thing that retains the water.

Zadržava is the 3rd person singular present tense.

It means he/she/it retains, and here it corresponds to it retains, because humus is grammatically singular.

The verb is from zadržavati (imperfective), and the present tense pattern here is:

• ja zadržavam = I retain
• ti zadržavaš = you retain
• on/ona/ono zadržava = he/she/it retains

So:

• Humus zadržava vodu. = Humus retains water.

Because this sentence expresses a general fact or ongoing property: humus has the ability to retain water.

In Croatian, for general truths, habits, repeated actions, and descriptions of how something works, you usually use the imperfective verb.

• zadržavati = imperfective, ongoing/repeated/general
• zadržati = perfective, completed result

So Humus zadržava vodu sounds natural for a general statement like Humus retains water.

A perfective form would usually not be used this way for a simple general statement.

Croatian does not have articles like a, an, and the.

So Humus zadržava vodu u posudi can be understood from context as:

• Humus retains water in the container
• The humus retains water in the container

English needs an article, but Croatian does not.

Whether the noun is definite or indefinite is usually understood from:

• context
• situation
• previous mention
• emphasis

Yes. Croatian word order is much more flexible than English word order because the case endings show grammatical roles.

The neutral order here is:

• Humus zadržava vodu u posudi.

But other orders are possible for emphasis, for example:

• Vodu zadržava humus u posudi.
• U posudi humus zadržava vodu.

These do not necessarily change the basic meaning, but they can change the focus or emphasis.

English relies heavily on word order. Croatian relies more on case endings and context.

Not necessarily. Posuda is a fairly general word meaning container, vessel, dish, or sometimes pot, depending on context.

So u posudi simply means in the container.

If you wanted to be more specific, Croatian might use another noun depending on the kind of container:

• čaša = glass
• boca = bottle
• zdjela = bowl
• lonac = pot
• tegla = jar / flowerpot in some contexts

So posuda is broad and practical, not highly specific.

Yes. Humus is a masculine inanimate noun.

Its nominative singular form is humus, which is also the form used in the sentence because it is the subject.

For example:

• humus = nominative singular
• humusa = genitive singular

So in this sentence, humus stays as humus because it is in the nominative.

Because Croatian usually does not need subject pronouns unless they are being emphasized.

The verb ending already shows the person and number:

• zadržava = he/she/it retains

Since the subject noun humus is already present, adding on would be unnecessary in normal speech.

Croatian often leaves pronouns out when the meaning is clear.

A rough pronunciation is:

za-dr-zha-va

A few useful sound notes:

• ž sounds like the s in measure or vision
• u sounds like oo in food
• a is usually a clear ah sound

So zadržava is approximately za-DR-zha-va, though exact stress can vary by region.

Yes, depending on context, a learner might wonder about that.

In practice, u posudi most naturally means in the container, and the whole sentence is understood as something like Humus retains water in the container. But Croatian, like English, can sometimes leave a little room for interpretation about what a phrase attaches to.

If you wanted to make it clearer that the humus is the thing located in the container, you could say:

• Humus u posudi zadržava vodu.

If you wanted to keep the original structure, context usually makes the intended meaning clear.