Flaša ima pola litra.

It can suggest either one from context, but most often it sounds like the bottle contains / holds half a liter.

If you want to be very clear:

• U flaši ima pola litra. = There is half a liter in the bottle.
• Flaša od pola litra = a half-liter bottle / a bottle with a 0.5 L capacity

So your sentence is understandable, but for pure capacity, Serbian often prefers flaša od pola litra.

Yes. Ima is the 3rd person singular of imati, meaning to have.

In Serbian, just like in English, have can be used for possession, but also for what something contains or holds:

• Kuća ima tri sobe. = The house has three rooms.
• Boca ima litar vode. = The bottle has / contains a liter of water.

So Flaša ima pola litra is literally The bottle has half a liter, but in natural English that is often better translated as The bottle holds/contains half a liter.

Because pola is the normal word used in quantity expressions like half a liter, half an hour, half a kilo:

• pola litra
• pola sata
• pola kilograma

Polovina is a noun meaning a half or one half, but it is not the usual choice in this structure.

Very roughly:

• pola litra = half a liter
• polovina = a half / one half

So in this sentence, pola is the natural choice.

Because after pola, the noun normally goes into the genitive singular.

The base form is:

• litar = liter

But after pola:

• pola litra = half a liter

This same pattern appears in many common expressions:

• pola sata = half an hour
• pola dana = half a day
• pola hleba = half a loaf of bread

So litra is the correct grammatical form here.

Flaša is in the nominative singular, because it is the subject of the sentence.

Structure:

• Flaša = subject, nominative singular
• ima = verb, 3rd person singular
• pola litra = quantity expression

So the grammar is basically:

• The bottle
  • has
    • half a liter

Because Serbian does not have articles like English a/an and the.

So flaša can mean:

• a bottle
• the bottle

You understand which one is meant from context.

That is why Flaša ima pola litra can translate as either:

• A bottle has half a liter
• The bottle has half a liter

depending on the situation.

Not if you mean the bottle holds half a liter.

Je means is, so Flaša je pola litra would sound wrong or unnatural for this meaning.

If you want to say the bottle’s size/capacity, better options are:

• Flaša je od pola litra. = The bottle is a half-liter bottle.
• Flaša ima pola litra. = The bottle holds/contains half a liter.

So for this sentence, ima is the right verb.

Serbian word order is fairly flexible, but the given order is neutral and natural.

• Flaša ima pola litra. = neutral
• U flaši ima pola litra. = focuses more on what is in the bottle
• Pola litra ima flaša. = possible, but marked and much less neutral

So a learner should usually stick with Flaša ima pola litra unless there is a special reason to emphasize something else.

Roughly:

• flaša ≈ FLA-sha

The important letter is š, which sounds like sh in ship.

So:

• fla = like fla
• ša = sha

Also, Serbian spelling is very phonetic, so once you know the letters, pronunciation becomes much easier.

Roughly:

• litra ≈ LEE-tra

A few helpful points:

• i is like the ee in see
• r is pronounced clearly, not swallowed
• a is a simple open a sound

So litra sounds compact and crisp: LEE-tra.