Serviser govori o dijagnostici.

Serviser usually means service technician, repair technician, or repairman, depending on context.

It is similar to mechanic, but not always identical:

• serviser is broader and can be used for someone who services or repairs devices, machines, appliances, electronics, cars, etc.
• mehaničar is more specifically mechanic, especially for vehicles or machinery.

So serviser in this sentence sounds like the technician or the repair person.

Govori is the 3rd person singular present tense of the verb govoriti, which means to speak or to talk.

So:

• ja govorim = I speak / I am speaking
• ti govoriš = you speak
• on/ona govori = he/she speaks

Because serviser is a singular subject, Serbian uses govori.

The preposition o means about in this kind of sentence.

So:

• govoriti o nečemu = to talk about something

That means after o, Serbian requires a specific case: the locative.

That is why the last word is not the basic dictionary form.

Because o requires the locative case, and dijagnostika changes form in the locative singular.

• dictionary form: dijagnostika
• after o: o dijagnostici

This is a normal pattern for many feminine nouns ending in -a:

• škola → o školi
• firma → o firmi
• dijagnostika → o dijagnostici

In this word, the k changes to c before i, which is a common sound/spelling change in Serbian.

The base form is dijagnostika.

That noun means diagnostics or diagnostic work/process, depending on context.

So:

• dijagnostika = nominative singular
• dijagnostici = locative singular

In this sentence, you are not seeing the base form because the preposition o forces the locative.

No. Serbian does not use articles like English a and the.

So Serviser govori o dijagnostici can mean:

• The technician is talking about diagnostics
• A technician is talking about diagnostics

Which one sounds best depends on context.

English needs an article, but Serbian usually does not.

It can mean either, depending on context.

Serviser govori o dijagnostici can mean:

• The technician is talking about diagnostics right now
• The technician talks about diagnostics in general / habitually

Serbian present tense often covers both meanings. Context tells you which one is intended.

Yes. Serbian word order is more flexible than English because case endings help show grammatical roles.

The neutral order here is:

• Serviser govori o dijagnostici.

But other orders may be possible for emphasis, such as:

• O dijagnostici govori serviser.
  = It is the technician who is talking about diagnostics.

That said, the original order is the most straightforward and natural for a basic statement.

A rough pronunciation guide for an English speaker is:

• Serviser ≈ SER-vee-ser
• govori ≈ GO-vo-ree
• o ≈ oh
• dijagnostici ≈ dee-yag-NO-stee-tsee

A few helpful notes:

• r in Serbian is trilled or tapped more than in English.
• j is pronounced like English y in yes.
• c is pronounced ts.
• Stress is not usually marked in normal writing, so learners usually pick it up by listening.

Yes, very normal.

A very common Serbian pattern is:

• govoriti o + locative = to talk/speak about

Examples:

• Govorim o poslu. = I’m talking about work.
• Pričamo o filmu. = We’re talking about the movie.
• On govori o problemu. = He is talking about the problem.

You may also see pričati o, which often feels a bit more like talk about in everyday speech, while govoriti o is also very standard and natural.

It sounds neutral, but slightly technical because of the word dijagnostika.

• Serviser is common and practical vocabulary.
• dijagnostika is a technical or professional term.

So the whole sentence would sound very natural in contexts like:

• car repair
• electronics repair
• appliance servicing
• IT or technical support

It is not overly formal, just professional or technical in topic.