Ik zit nog in mijn pyjama te lezen.

Yes, zit is the present tense of zitten (to sit), and literally it does mean sit / am sitting.

But in Dutch, verbs like zitten (sit), staan (stand), liggen (lie), and lopen (walk) are often used to describe an ongoing action. So ik zit te lezen means:

• literally: I am sitting reading
• more naturally: I’m reading, with the idea that I’m seated

So the sentence does suggest the speaker is sitting, but it also works as a very natural Dutch way to express an action in progress.

Here nog means still.

So it adds the idea that the situation is continuing:

• Ik zit in mijn pyjama te lezen = I’m reading in my pyjamas
• Ik zit nog in mijn pyjama te lezen = I’m still reading in my pyjamas / I’m reading in my pyjamas still

It often implies that this may be a bit later than expected, or that the state has not changed yet.

Dutch commonly uses in with clothes to mean wearing them.

So:

• in mijn pyjama = in my pyjamas / wearing my pyjamas

This is very normal Dutch. English also says in my pyjamas, so this part matches English fairly well.

In Dutch, pyjama is normally treated as a singular noun when referring to the garment you are wearing.

So:

• mijn pyjama = my pyjamas

Even though English usually uses a plural form, Dutch usually does not here.

You can make it plural, pyjama’s, but that would mean multiple sets of pyjamas, for example in a shop:

• Ik koop twee pyjama’s = I’m buying two pairs/sets of pyjamas

Lezen is the infinitive to read.
In this construction, te is used with verbs like zitten, staan, liggen, and lopen to express an ongoing activity.

So:

• ik zit te lezen = I am reading
• literally: I sit to read, but that literal English translation is misleading

You should learn zitten te + infinitive as a set pattern meaning something like:

• to be sitting and doing something
• or more naturally, to be doing something while seated

Because Dutch main clauses usually put the finite verb in second position, while other verbs often go to the end.

In this sentence:

• Ik = subject
• zit = finite verb, so it comes early
• nog in mijn pyjama = middle part
• te lezen = infinitive phrase at the end

That final position is very typical in Dutch.

Yes, that is also possible.

Dutch has two common ways to express an ongoing action:

• Ik zit nog in mijn pyjama te lezen
• Ik ben nog in mijn pyjama aan het lezen

The difference is roughly this:

• zitten te lezen emphasizes the posture or physical situation a bit more
• aan het lezen zijn is a more general progressive, like am reading

So both are natural, but zit ... te lezen feels especially suitable if the speaker is sitting somewhere reading.

Yes, you can, and it is grammatical.

That version is simpler:

• Ik lees nog in mijn pyjama = I still read / I’m still reading in my pyjamas

Compared with Ik zit nog in mijn pyjama te lezen, it gives less detail about the physical scene. The version with zit ... te lezen sounds more vivid and more clearly ongoing.

Yes. This is a very common Dutch pattern.

For example:

• Ik sta te lezen = I’m standing reading
• Ik lig te lezen = I’m lying reading
• Ik loop te lezen = I’m walking around reading

So Dutch often chooses a posture/movement verb depending on the physical position of the person doing the action.

It often suggests both.

Because of nog in mijn pyjama and zit ... te lezen, the sentence can sound quite visual and descriptive. It gives a little scene:

• the speaker is still in their pyjamas
• they are sitting
• they are reading

So although the basic meaning is straightforward, the Dutch wording also creates a cozy, everyday image.

A common Dutch pronunciation is roughly:

• pie-JAA-maa

The stress is usually on the middle syllable: ja.

A rough English approximation would be:

• pee-YAH-mah

The spelling is the same as in English except that Dutch pronunciation is different.