Learn Hardcore Czech: Moje kolegyně říká, že v pátek nechce dělat nic důležitého v práci. - My female colleague says that on Friday she doesn't want to do anything important at work.

moje kolegyně – neutral, most common spoken form.
má kolegyně – a shorter, more formal/literary variant of moje. You will see it more in writing, speeches, etc.
mojí kolegyní – different case (instrumental singular), meaning “with my colleague / as my colleague.”
- Example: S mojí kolegyní pracuju v jedné kanceláři. – I work in the same office as my colleague.

In the sentence given, kolegyně is the subject (nominative), so the correct possessive is moje (or stylistically má):
Moje / Má kolegyně říká…

How do I know that kolegyně means a female colleague?

The suffix -yně almost always marks a female person:

kolega → kolegyně (male colleague → female colleague)
učitel → učitelka (teacher → female teacher, here -ka is used)
princ → princezna (prince → princess)

So:

kolega = (usually) male colleague
kolegyně = explicitly female colleague

English colleague doesn’t mark gender, but Czech usually does, so you pick kolega or kolegyně depending on the person.

Why is the verb říká used and not a past tense like řekla?

Czech has two aspectually related verbs:

říkat (imperfective) – to say, to be saying, to say repeatedly/habitually
říct / říci (perfective) – to say once, to have said (completed act)

říká is present tense of říkat, and here it suggests:

either she is saying this (now):
Moje kolegyně říká, že… – My colleague is saying that…
or she says this in general / regularly:
My colleague (often) says that on Fridays she doesn’t want to do anything important at work.

If you say:

Moje kolegyně řekla, že… – My colleague said that… (a specific past occasion).

Why is there no ona (she) before nechce?

Czech is a pro-drop language: subject pronouns are normally left out when obvious from context.

The subject Moje kolegyně is already stated in the main clause.
In the subordinate clause: že v pátek nechce dělat…, the understood subject is still she (the colleague), so ona is not needed.

You’d only add ona for emphasis or contrast:

…že ona v pátek nechce dělat nic důležitého…
– that she (as opposed to someone else) doesn’t want to do anything important on Friday.

What case is v pátek, and why is it different from v práci?

Both use the preposition v, but with different meanings and therefore different cases:

v pátek – time: on Friday
- Here v means “on / during (a day)” → it takes the accusative.
- pátek in the accusative is the same form as nominative: pátek.
- So v pátek = on Friday.
v práci – location: at work
- Here v means “in/at (a place)” → it takes the locative.
- Locative of práce is práci.
- So v práci = at work / in the workplace.

Same preposition, different case because the meaning (time vs. location) is different.

Could I change the word order in the second clause, like že nechce v pátek dělat nic důležitého v práci?

Yes. Czech word order is fairly flexible. All of these are possible and natural:

že v pátek nechce dělat nic důležitého v práci
že nechce v pátek dělat nic důležitého v práci
že v pátek v práci nechce dělat nic důležitého

The main differences are in rhythm and emphasis:

Putting v pátek first highlights the time: On Friday, she doesn’t want…
Putting v práci earlier highlights the place.

For a learner, your original order is perfectly fine and neutral.

What exactly does nechce mean here? Is it like “doesn’t want to” or “doesn’t feel like”?

nechce is 3rd person singular of chtít – to want.

nechce dělat… – she doesn’t want to do…

In everyday spoken Czech, nechce se jí dělat… is closer to “she doesn’t feel like doing…”.
So:

nechce dělat nic důležitého – she consciously doesn’t want to do anything important.
nechce se jí dělat nic důležitého – she can’t be bothered / doesn’t feel like doing anything important.

Your sentence is the straightforward “doesn’t want to” version.

Why is it dělat, not udělat?

Czech distinguishes between imperfective and perfective verbs:

dělat (imperfective) – to do (in general, ongoing, repeated, without focus on completion)
udělat (perfective) – to do / to get done (one complete action)

In this sentence the colleague is speaking about any important work in general, not one specific task she wants to complete:

nechce dělat nic důležitého – she doesn’t want to do any important things (as activities).

If you said:

nechce udělat nic důležitého – it would lean more toward “she doesn’t want to get any important thing done” (no important result).

Why do we say nechce dělat nic… instead of something like chce nedělat nic…?

Negation in Czech normally goes on the verb, and then negative pronouns like nic are added:

nechce dělat nic – she does not want to do anything.
chce dělat něco – she wants to do something.

Notice the pattern:

Negative → use ne- on the verb plus nic / nikdo / nikdy:
- Nikdo nic nedělá. – Nobody is doing anything.
Positive → no ne-, and use něco / někdo / někdy:
- Někdo něco dělá. – Somebody is doing something.

chce nedělat nic would be understood, but it sounds clumsy; it focuses on the act of not-doing, not on absence of desire. The natural way is nechce dělat nic.

Why is it nic důležitého and not nic důležitý or nic důležité?

Two things are happening here:

nic is treated as grammatically neuter singular.
After nic, Czech usually uses the genitive case for adjectives and nouns.

So:

nic (čeho?) důležitého – nothing important
- důležitého = neuter singular genitive of důležitý.

Compare:

něco důležitého – something important
nic důležitého – nothing important
něco nového / nic nového
něco zajímavého / nic zajímavého

Using nic důležitý or nic důležité would be wrong here; the form must agree (neuter, genitive) with the nic pattern.

Why is v práci used instead of na práci?

v and na can both translate as at / in / on, but their use is quite fixed with certain nouns.

v práci is the standard expression meaning “at work (place)”.
- Locative: v práci, v kanceláři, v nemocnici, v obchodě.
na práci usually means “for work” (purpose), not location:
- Nemám čas na práci. – I don’t have time for work.
- Nástroje na práci. – Tools for work.

So if you want to say at work, always use v práci.

Can I move v práci earlier, like …že v pátek v práci nechce dělat nic důležitého?

Yes, that’s perfectly grammatical:

…že v pátek v práci nechce dělat nic důležitého.

This version puts time (v pátek) and place (v práci) together at the beginning of the clause and then tells you what she doesn’t want to do. It can sound slightly more structured or formal, but it’s still natural.

Three good variants, all correct:

…že v pátek nechce dělat nic důležitého v práci.
…že v pátek v práci nechce dělat nic důležitého.
…že v práci v pátek nechce dělat nic důležitého. (less common, but possible)

The basic meaning stays the same: on Friday, at work, she doesn’t want to do anything important.