Komšinica kaže da će doći sa cvećem.

Komšinica means female neighbor, while komšija is usually male neighbor.

So:

• komšinica kaže... = the female neighbor says...
• komšija kaže... = the male neighbor says...

The ending -ica is a common feminine ending in Serbian nouns.

In Serbian, subject pronouns are often omitted because the verb form already shows who the subject is.

Here, kaže means he/she says, and the noun komšinica already tells us who is speaking, so adding ona would be unnecessary in normal usage.

• Komšinica kaže... = natural
• Ona kaže... = possible, but only if you want emphasis or contrast
• Komšinica ona kaže... = generally not needed

Kaže is the 3rd person singular present tense of kazati / reći, meaning to say.

So kaže can mean:

• says
• is saying
• sometimes even said, depending on context in conversation, though the basic form is present

In this sentence, it simply means:

• Komšinica kaže... = The neighbor says...

Serbian often uses da + verb where English would use an infinitive.

Here the structure is:

• kaže da... = says that...
• će doći = will come

So:

• Komšinica kaže da će doći... literally = The neighbor says that she will come...

This is very normal Serbian sentence structure. English sometimes drops that, but Serbian usually keeps da in this kind of clause.

Će doći is a standard way to form the future tense in Serbian.

It consists of:

• će = the future auxiliary, here meaning will
• doći = to come / to arrive

So:

• će doći = will come

The full future auxiliary changes by person:

• ću = I will
• ćeš = you will
• će = he/she/it will
• ćemo = we will
• ćete = you will
• će = they will

Here it is će because the subject is komšinica = she.

Doći means to come / to arrive and is a perfective verb. It focuses on reaching the destination.

Compare:

• doći = to come, to arrive once, as a completed action
• dolaziti = to be coming / to come regularly / to come repeatedly
• ići = to go

Since the sentence means that she will come on a particular occasion, doći is the natural choice.

Examples:

• Sutra će doći. = She will come tomorrow.
• Često dolazi. = She often comes.

Sa cvećem means with flowers, and cvećem is in the instrumental case.

After sa / s meaning with, Serbian normally uses the instrumental:

• sa cvećem = with flowers
• sa prijateljem = with a friend
• sa sestrom = with (my) sister

So the pattern is:

• sa + instrumental

Because cveće is the basic dictionary form, but after sa it must change into the instrumental case.

Forms:

• cveće = nominative / basic form
• cvećem = instrumental

So:

• Cveće je lepo. = The flowers / the flower arrangement is beautiful.
• Doći će sa cvećem. = She will come with flowers.

Also, cveće often works like a collective noun meaning flowers in general, not necessarily one single flower.

Yes, but in meaning they are the same here: both mean with.

• s is the shorter form
• sa is often used for easier pronunciation, especially before certain consonant clusters

So both can exist, but sa cvećem is the natural form here.

Other examples:

• s njim = with him
• sa sestrom = with my sister
• sa cvećem = with flowers

In everyday speech, choosing sa often just makes the phrase smoother to say.

Komšinica is in the nominative case because it is the subject of the sentence.

It is the person doing the action of kaže.

So:

• komšinica = nominative subject
• cvećem = instrumental after sa

This is a very common pattern in Serbian: subject in nominative, then another noun in a different case depending on the preposition.

Yes. Serbian present tense often covers both the simple present and the present continuous in English, depending on context.

So Komšinica kaže... could be understood as:

• The neighbor says...
• The neighbor is saying...

In most neutral translations, says is the best choice.

Yes, Serbian word order is more flexible than English word order, although the original sentence is the most neutral.

Neutral order:

• Komšinica kaže da će doći sa cvećem.

Other possible orders may be used for emphasis:

• Kaže komšinica da će doći sa cvećem.
• Sa cvećem će doći, kaže komšinica.

These alternatives change emphasis or style, but not the core meaning.

The letter ć is a soft consonant, somewhat like a very soft ty sound, though there is no exact English equivalent.

Roughly:

• cveće sounds approximately like TSVEH-tyeh
• cvećem sounds approximately like TSVEH-tyem

A few notes:

• cv at the beginning is pronounced together, without a vowel in between
• ć is softer than č
• č is more like English ch
• ć is a softer, more palatal sound

English speakers often find č and ć hard to distinguish at first, and that is completely normal.