Koleginica koja radi sa mnom danas nije u kancelariji.

Koleginica means female colleague, while kolega usually means male colleague (and in some contexts can also be used more generally for colleague).

In this sentence, koleginica tells you the person being talked about is a woman.

• kolega = a male colleague / colleague
• koleginica = a female colleague

Koja means who in the sense of a relative pronoun, connecting koleginica with extra information about her:

• Koleginica = the colleague
• koja radi sa mnom = who works with me

So koja refers back to koleginica.

It changes form depending on gender, number, and case. Here it is koja because it refers to koleginica, which is feminine singular.

Compare:

• čovek koji radi... = the man who works...
• žena koja radi... = the woman who works...

Serbian word order is fairly flexible, but this sentence uses a very natural structure:

• Koleginica
• koja radi sa mnom
• danas nije u kancelariji

The relative clause koja radi sa mnom comes right after the noun it describes, just like English who works with me.

You can move some parts around for emphasis, especially danas, but the given order is neutral and natural.

For example:

• Koleginica koja radi sa mnom danas nije u kancelariji.
• Koleginica koja radi sa mnom nije danas u kancelariji.
• Danas koleginica koja radi sa mnom nije u kancelariji.

All are possible, but the original sounds very normal.

Radi is the correct 3rd person singular present tense form of raditi (to work), because the subject is koleginica = she.

Present tense of raditi:

• ja radim = I work
• ti radiš = you work
• on/ona radi = he/she works
• mi radimo = we work
• vi radite = you work
• oni/one rade = they work

So:

• koleginica radi = the colleague works

After the preposition sa (with), Serbian normally uses the instrumental case.

The pronoun ja changes in the instrumental:

• ja = I
• mnom = with me / by me (instrumental form used with sa)

So:

• sa mnom = with me

This is just something you have to learn as a pronoun form.

A few similar examples:

• sa tobom = with you
• sa njim = with him
• sa njom = with her

Both sa mnom and s mnom exist, but sa mnom is the standard and most common form learners should use.

The preposition is basically s/sa = with. The longer form sa is often used to make pronunciation easier, especially before certain consonant clusters.

So in practice:

• sa mnom = the normal form to use
• s mnom = possible in some contexts/styles, but less common for learners

If you are unsure, use sa.

Kancelariji is in the locative case, because it follows u when u means in a place.

• u kancelariji = in the office

Here the meaning is location, not motion. The colleague is in the office or not in the office.

Compare:

• u kancelariji = in the office → locative
• u kancelariju = into the office → accusative

So:

• nije u kancelariji = is not in the office
• ide u kancelariju = is going into the office

Because the preposition u requires different cases depending on meaning.

Here it means in the office (location), so you need the locative:

• kancelarija = nominative
• u kancelariji = locative

If you said u kancelarija, that would be ungrammatical.

A useful rule:

• u + locative = in, at
• u + accusative = into, to

In Serbian, the negative form of to be is usually written as one word:

• sam → nisam
• si → nisi
• je → nije
• smo → nismo
• ste → niste
• su → nisu

So:

• ona je u kancelariji = she is in the office
• ona nije u kancelariji = she is not in the office

You do not normally say ne je.

Yes, in a way.

The sentence has two verb parts:

1. koja radi sa mnom = who works with me
2. danas nije u kancelariji = today is not in the office

In the second part, Serbian does not need to repeat a subject pronoun like ona (she) because it is already clear from koleginica.

So the full sense is:

• The female colleague who works with me is not in the office today.

But Serbian naturally leaves out ona because the noun already tells you who the subject is.

Danas means today, and it tells you when the main statement is true:

• nije u kancelariji danas = is not in the office today

So it belongs with the main clause, not really with radi sa mnom.

The meaning is:

• the colleague who works with me
• is not in the office today

Even though danas is placed before nije, it refers to the time of the whole main statement.

Yes. Serbian allows some flexibility in word order.

Possible versions include:

• Koleginica koja radi sa mnom danas nije u kancelariji.
• Koleginica koja radi sa mnom nije danas u kancelariji.
• Danas koleginica koja radi sa mnom nije u kancelariji.

These all mean roughly the same thing, but the focus changes slightly.

• danas near the beginning can emphasize today
• nije danas can contrast today with another day

The original sentence is natural and neutral.

Because this relative clause is restrictive: it identifies which colleague is meant.

In English, this is like:

• The colleague who works with me...

No comma is needed when the clause defines the noun.

If it were extra, non-essential information, Serbian punctuation could be different, but here koja radi sa mnom is necessary to specify which colleague we mean.

So no comma is the normal choice.

Yes, the Serbian present tense often covers both ideas, depending on context.

• radi sa mnom can mean works with me in a general sense
• it can also mean is working with me in a current/ongoing sense

In this sentence, the more natural interpretation is probably general:

• the colleague who works with me

But context can make it more immediate if needed.

In this sentence, you know from the noun koleginica, not from the present tense verb.

The verb forms:

• radi
• nije

do not by themselves show feminine gender here.

Gender is shown by:

• koleginica = feminine noun
• koja = feminine relative pronoun

So the sentence clearly refers to a woman because of those words.

It is the most common standard word for office.

• kancelarija = office
• u kancelariji = in the office

Depending on context, Serbian might also use words like ured in some regional varieties, but kancelarija is the safest and most widely recognized word to learn.

It looks unusual because it is an old pronoun form that learners usually just memorize.

mnom is roughly pronounced like mnom, with the mn cluster clearly pronounced. It may feel awkward at first because English does not often begin or center syllables around combinations like this.

You will see similar forms with pronouns after prepositions:

• sa mnom = with me
• preda mnom = in front of me
• za mnom = behind me / after me

It is best to learn sa mnom as a fixed phrase at first.

No. Standard Serbian writes it as sa mnom, two words.

Correct:

• sa mnom

Incorrect:

• samnom

This is a very common spelling mistake even among native speakers online, so it is especially worth memorizing.

A helpful breakdown is:

• Koleginica = subject noun
• koja radi sa mnom = relative clause describing the subject
• danas = time expression
• nije u kancelariji = main predicate

So the pattern is:

[noun] + [who ...] + [time] + [is not ...]

More literally:

• Koleginica = female colleague
• koja radi sa mnom = who works with me
• danas = today
• nije u kancelariji = is not in the office

This is a very useful model for building similar Serbian sentences.