Treba mi kilogram brašna.

In Serbian, trebati is very often used in an impersonal-style pattern:

Treba mi + noun

Literally, this is closer to It is needed to me, but the natural English translation is I need.

So:

• Treba mi kilogram brašna. = I need a kilogram of flour.

This is one of the most common everyday ways to say that you need an object.

You may also hear forms like Trebam kilogram brašna, but Treba mi... is extremely common and often sounds more natural in many situations.

Mi is the short form of meni, meaning to me.

So in this sentence:

• treba = is needed
• mi = to me

Together, treba mi means I need.

Other examples:

• Treba mi voda. = I need water.
• Treba mi pomoć. = I need help.
• Treba mi novi telefon. = I need a new phone.

Because after numbers and quantity expressions, Serbian often uses specific case/number patterns.

Here, kilogram is the quantity word itself, and it stays in the form you would expect after jedan or as a basic measure noun:

• kilogram brašna = a kilogram of flour

Compare:

• jedan kilogram = one kilogram
• dva kilograma = two kilograms
• pet kilograma = five kilograms

So in your sentence, kilogram is singular because it means one kilogram.

Because after a measure word like kilogram, Serbian usually puts the substance being measured into the genitive case.

So:

• brašno = flour (dictionary/basic form, nominative)
• brašna = of flour (genitive)

That is why:

• kilogram brašna = a kilogram of flour
• čaša vode = a glass of water
• flaša mleka = a bottle of milk

This is very similar to English of flour, even though Serbian usually does not use a separate word for of here.

Yes, that is a good way to think about it.

Kilogram brašna literally works like:

• kilogram of flour

Serbian usually expresses this of relationship through the genitive case rather than with a separate word.

So:

• kilogram brašna = kilogram of flour
• šolja čaja = cup of tea
• komad hleba = piece of bread

Yes, you may hear that, and in some regions it is quite normal.

However, many learners are first taught Treba mi kilogram brašna because it is a very common and widely useful pattern for expressing need.

A simple practical rule is:

• for I need + thing, Treba mi... is very safe and natural

Examples:

• Treba mi olovka. = I need a pencil.
• Treba mi malo vremena. = I need a little time.
• Treba mi kilogram brašna. = I need a kilogram of flour.

Because Serbian often leaves out subject pronouns when they are not necessary.

English usually needs I, but Serbian often does not.

In Treba mi kilogram brašna, the idea of the experiencer is already shown by mi = to me, so ja is unnecessary.

You could add meni for emphasis:

• Meni treba kilogram brašna. = I need a kilogram of flour.

But in normal neutral speech, Treba mi kilogram brašna is enough.

Yes. Serbian word order is fairly flexible, though some versions sound more neutral than others.

The most neutral version is:

• Treba mi kilogram brašna.

You might also hear:

• Kilogram brašna mi treba.
• Meni treba kilogram brašna.

These can shift emphasis slightly:

• Meni treba... emphasizes to me / I
• Kilogram brašna... emphasizes the thing needed

For learners, the safest default is the original order:

Treba mi kilogram brašna.

A simple approximate pronunciation for an English speaker is:

TREH-bah mee KEE-loh-grahm BRAHSH-nah

A few helpful points:

• r in Serbian is rolled or tapped
• j is pronounced like English y
• š sounds like sh
• stress can vary by dialect, but this approximation will be understood

Word by word:

• Treba ≈ TREH-bah
• mi ≈ mee
• kilogram ≈ KEE-loh-grahm
• brašna ≈ BRAHSH-nah

Like flour in English, brašno is normally treated as an uncountable substance noun.

That is why you usually measure it with words like:

• kilogram brašna = a kilogram of flour
• malo brašna = a little flour
• mnogo brašna = a lot of flour

You would not normally count it directly as separate individual items.

Yes, absolutely. This sentence is a very useful model.

Pattern:

Treba mi + measure word + noun in genitive

Examples:

• Treba mi litar mleka. = I need a liter of milk.
• Treba mi kilogram šećera. = I need a kilogram of sugar.
• Treba mi paket pirinča. = I need a packet of rice.
• Treba mi flaša ulja. = I need a bottle of oil.

This is a very common structure in everyday Serbian, especially when shopping or cooking.