Desni krvare zbog upale.

No. In this sentence, desni is a noun meaning gums.

This can confuse learners because Serbian also has adjective forms like desni related to right (the opposite of left) in other contexts. Here, though, the context makes it clear that desni means gums: they are the thing that bleed.

Because desni is normally used as a plural noun in everyday Serbian, similar to English gums.

That is why the verb is also plural:

• desni = gums
• krvare = bleed / are bleeding

You also get plural agreement with adjectives, for example:

• zdrave desni = healthy gums
• osetljive desni = sensitive gums

Grammatically, desni takes feminine plural agreement.

Krvare is the 3rd person plural present tense of the verb krvariti, which means to bleed.

So:

• ja krvarim = I bleed / am bleeding
• ti krvariš = you bleed / are bleeding
• oni/one krvare = they bleed / are bleeding

In this sentence, krvare can mean either:

• bleed
  or
• are bleeding

The exact English wording depends on context.

Because the preposition zbog requires the genitive case.

The basic dictionary form is:

• upala = inflammation

After zbog, it changes to the genitive:

• zbog upale = because of inflammation

So the structure is:

• zbog
  • genitive

A few similar examples:

• zbog bolesti = because of illness
• zbog kiše = because of rain
• zbog problema = because of a problem / because of problems

Zbog means because of or due to.

It is used with a noun phrase, not a full clause. So here:

• zbog upale = because of inflammation

This is different from jer, which means because and introduces a full clause:

• Desni krvare zbog upale. = The gums bleed because of inflammation.
• Desni krvare jer su upaljene. = The gums are bleeding because they are inflamed.

So:

• zbog
  • noun
• jer
  • clause

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

Also, with body parts, Serbian often leaves out possessive words like my or your when the meaning is obvious from context.

So Desni krvare zbog upale could mean things like:

• The gums bleed because of inflammation
• My gums are bleeding because of inflammation
• Your gums are bleeding because of inflammation

If you want to make possession explicit, you can say:

• Moje desni krvare zbog upale. = My gums are bleeding because of inflammation.

Yes. Serbian word order is fairly flexible.

Desni krvare zbog upale is a neutral, natural order:

• desni = subject
• krvare = verb
• zbog upale = cause

But you can move parts around for emphasis, for example:

• Zbog upale desni krvare.
  This puts more emphasis on the cause.

The meaning stays basically the same because the case marking helps show how the words relate to each other.

Literally, upala means inflammation.

In everyday medical language, learners sometimes want to translate it as infection, but that is not always exact. An inflammation can be caused by an infection, but upala itself means inflammation.

So in this sentence, the most accurate basic meaning is:

• because of inflammation

A rough English-friendly approximation is:

DES-nee KRR-va-re ZBOG oo-PA-le

A few pronunciation notes:

• desni: the e is like in met, and i is like ee
• krvare: the r is tapped or rolled, not the English r
• zbog: both consonants at the start are pronounced, zb-
• upale: u sounds like oo

In Serbian, letters are pronounced quite consistently, so once you know the sounds, the spelling is very reliable.