Paradajz je u kesi.

• paradajz = tomato
• je = is
• u = in
• kesi = bag / the bag, in a case form required after u when it means location

So the sentence literally matches English very closely: Tomato is in bag, but natural English adds an article: The tomato is in the bag or A tomato is in the bag, depending on context.

Je is the 3rd person singular present tense of the verb biti (to be).

So:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is

Since paradajz is singular, Serbian uses je:
Paradajz je u kesi = The tomato is in the bag.

Because after u meaning in for a fixed location, Serbian uses the locative case.

The noun kesa (bag) is a feminine noun, and its locative singular form is kesi.

So:

• kesa = bag (basic dictionary form, nominative)
• u kesi = in the bag (locative)

This is a very common pattern:

• u kući = in the house
• u školi = in the school
• u sobi = in the room

It is the locative singular.

With u:

• location → usually locative
• direction/movement into → usually accusative

So:

• Paradajz je u kesi. = The tomato is in the bag. → location → locative
• Stavljam paradajz u kesu. = I am putting the tomato into the bag. → movement/direction → accusative

This location-vs-direction contrast is very important in Serbian.

Use u + accusative when there is movement into something.

Compare:

• Paradajz je u kesi. = The tomato is in the bag.

  • no movement
  • locative

• Stavio sam paradajz u kesu. = I put the tomato into the bag.

  • movement into the bag
  • accusative

For this noun:

• kesa = nominative
• kesu = accusative singular
• kesi = locative singular

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

So paradajz can mean:

• a tomato
• the tomato

And u kesi can mean:

• in a bag
• in the bag

The exact meaning depends on context.

That means Paradajz je u kesi could be understood as:

• The tomato is in the bag
• A tomato is in a bag
• The tomato is in a bag

English forces you to choose an article; Serbian usually does not.

Yes, paradajz is singular here.

The usual plural is paradajzi:

• Paradajz je u kesi. = The tomato is in the bag.
• Paradajzi su u kesi. = The tomatoes are in the bag.

Notice that the verb also changes:

• je = is
• su = are

Yes. Serbian word order is more flexible than English, although the basic version here is very natural:

• Paradajz je u kesi.

You can also say:

• U kesi je paradajz.

This still means the same thing, but it shifts the emphasis a bit, roughly like:

• The tomato is in the bag.
• In the bag is the tomato. / It’s the tomato that’s in the bag.

One important detail: je is a clitic, so it typically appears in the second position of the sentence or clause.

A rough pronunciation guide for an English speaker:

• paradajz ≈ pa-ra-dahyz
• je ≈ yeh
• u ≈ oo
• kesi ≈ keh-see

A more careful note:

• j in Serbian is pronounced like English y in yes
• z is like English z
• s is always like English s, never like z
• vowels are usually clear and simple

So je is not like English jee; it sounds more like ye.

Yes, kesa is a very common everyday word for a bag, especially a shopping bag or plastic bag.

Depending on context, Serbian also has other words, for example:

• torba = bag, handbag, shoulder bag, school bag
• vreća = sack, large bag

So in a sentence like this, u kesi strongly suggests in a bag, often a light bag such as a shopping bag.

Yes. Besides paradajz, you may also see rajčica.

• paradajz is very common in Serbian
• rajčica is much more common in Croatian, though Serbian speakers will usually understand it

So if you are learning standard Serbian, paradajz is the word you should definitely know.

In a normal full sentence like this, standard Serbian keeps je:

• Paradajz je u kesi.

Leaving it out would usually sound incomplete in ordinary speech. You might see omission in:

• headlines
• notes
• very informal fragments

But for normal grammar, keep je here.

In this sentence, it most naturally means a tomato / the tomato, that is, a single tomato.

But in Serbian, some food words can sometimes behave a bit like mass nouns depending on context. Still, with je and this simple sentence, most learners should understand it as one tomato.

If you clearly mean plural tomatoes, use:

• Paradajzi su u kesi. = The tomatoes are in the bag.

If you mean tomato sauce, tomato purée, or something similar, Serbian would normally use a more specific expression, not this sentence.