Wilt u niet zo schreeuwen? Mijn dochter ligt in haar pyjama te slapen.

Because Dutch yes/no questions usually put the finite verb before the subject. So:

• U wilt niet zo schreeuwen. = a statement
• Wilt u niet zo schreeuwen? = a question / polite request

In this sentence, that question form is being used to make a polite request.

Yes. U is the polite/formal way to say you in Dutch.

An informal version to one person would be:

Wil je niet zo schreeuwen?

To more than one person informally, you could say:

Willen jullie niet zo schreeuwen?

So u tells you the speaker is being polite, distant, or formal.

With u, both wilt u and wil u can be heard in modern Dutch. Wilt u is very common and often feels a bit more careful or traditional. Wil u is also accepted and common in everyday language.

So Wilt u niet zo schreeuwen? is completely normal Dutch.

A question like Wilt u niet zo schreeuwen? sounds more polite than a direct imperative such as:

Schreeuw niet zo.

The direct command is stronger and more abrupt. The question form softens it, even though the speaker is still clearly annoyed or urgent.

Niet means not, and zo here means something like so much, so loudly, or like that.

So niet zo schreeuwen is not a word-for-word match to English, but it means something like:

• not shout so much
• not shout so loudly
• not shout like that

The exact English wording depends on context.

Because willen is a modal verb. In Dutch, modal verbs are followed by another verb in the infinitive:

• Ik wil slapen.
• U wilt niet schreeuwen.

In a main clause, the finite verb goes in second position, and the infinitive usually goes toward the end. That is why you get:

Wilt u niet zo schreeuwen?

Both are possible, but they are not exactly the same.

• Mijn dochter slaapt. = My daughter is asleep / sleeps.
• Mijn dochter ligt te slapen. = My daughter is lying asleep / is sleeping there right now.

The version with ligt ... te slapen makes the scene more vivid and emphasizes the ongoing situation. It strongly suggests she is lying in bed.

In this sentence, te is part of a common Dutch pattern:

• liggen te + infinitive
• zitten te + infinitive
• staan te + infinitive

Examples:

• Hij zit te lezen. = He is sitting reading.
• Ze staat te wachten. = She is standing waiting.
• Mijn dochter ligt te slapen. = My daughter is lying sleeping.

So te is not translated separately here. It helps form this progressive-style construction.

Dutch often uses posture verbs where English would simply use be. The three big ones are:

• liggen = lie
• zitten = sit
• staan = stand

Since the daughter is presumably in bed, ligt is the natural choice. It tells you her physical position as well as the action.

That is normal Dutch word order. The finite verb comes early, and other information often comes before the final infinitive part.

So:

Mijn dochter ligt in haar pyjama te slapen

sounds very natural.

You may also hear other orders in Dutch, but this version is smooth and neutral. Here in haar pyjama gives extra information about the daughter before the sentence ends with the verbal part te slapen.

Because haar means her.

• mijn = my
• jouw/je = your
• zijn = his
• haar = her

So haar pyjama means her pajamas / her pajama outfit.

In Dutch, pyjama is usually a singular noun:

• een pyjama = pajamas / a pajama set

So in haar pyjama is exactly what you would expect in Dutch, even though English often uses the plural pajamas.

Yes. That is also possible Dutch.

• Mijn dochter is aan het slapen. = My daughter is sleeping.
• Mijn dochter ligt te slapen. = My daughter is lying asleep / sleeping lying down.

The aan het + infinitive form is a general progressive construction. The ligt te slapen version is more specific and paints the picture of her lying in bed.

Normally, modern Dutch writes u with a lowercase letter, as in this sentence.

A capital U can appear in very formal letters or messages as an extra sign of politeness, but in ordinary writing u is standard.