Z kuchni słychać śmiech dzieci.

Because z kuchni means from the kitchen, which shows the source of the sound.

• z kuchni = from the kitchen
• w kuchni = in the kitchen

So:

• Z kuchni słychać śmiech dzieci. = The laughter of children can be heard coming from the kitchen.
• W kuchni... would mean something is happening inside the kitchen, not necessarily coming out of it.

Also, after the preposition z, Polish uses the genitive case, so kuchnia becomes kuchni.

Słychać means something like:

• one can hear
• it can be heard
• you can hear

It is an impersonal form. That means the sentence does not say who is hearing the sound. The focus is just on the fact that the sound is audible.

So Z kuchni słychać śmiech dzieci is very natural Polish for saying that the sound of children laughing is audible from the kitchen.

Słyszeć is the basic verb meaning to hear.
Słychać is a special impersonal form built from that verb and means can be heard / is audible.

Compare:

• Słyszę śmiech dzieci. = I hear the children’s laughter.
• Słychać śmiech dzieci. = Children’s laughter can be heard.

So in this sentence, słychać is used because the speaker is not emphasizing the listener, only the sound itself.

Because in Polish, when one noun belongs to or is associated with another noun, the second noun often goes into the genitive.

Here:

• śmiech = laughter
• dzieci = of children

So śmiech dzieci literally means the laughter of children.

This is a very common pattern in Polish:

• dom brata = brother’s house / the house of the brother
• głos kobiety = the woman’s voice
• śmiech dzieci = children’s laughter

Here dzieci is in the genitive plural.

The base word is:

• dziecko = child

Its plural is:

• dzieci = children

And the genitive plural is also:

• dzieci = of children

So the form looks the same as the nominative plural, but here the function is different. In śmiech dzieci, it clearly means the laughter of children, so it is genitive.

No. Dzieci is not the subject here.

The sentence is impersonal because of słychać. There is no normal subject like in an English sentence such as The children are laughing.

What we have is:

• z kuchni = from the kitchen
• słychać = can be heard
• śmiech dzieci = the laughter of children

So the main idea is not children do something, but rather children’s laughter is audible.

Polish often leaves out dummy subjects like English it.

English says:

• It can be heard from the kitchen.

But Polish usually does not need an equivalent of that empty it. The verb form itself is enough:

• Słychać... = It can be heard / One can hear...

This is very normal in Polish and one of the things that often feels unusual to English speakers at first.

Yes. Polish word order is more flexible than English, although different orders can change the emphasis.

The neutral version here is:

• Z kuchni słychać śmiech dzieci.

But you might also hear:

• Śmiech dzieci słychać z kuchni.
• Słychać z kuchni śmiech dzieci.

These all mean roughly the same thing, but the focus shifts slightly:

• starting with z kuchni emphasizes where the sound comes from
• starting with śmiech dzieci emphasizes what is being heard
• starting with słychać emphasizes the perception itself

Yes, but it means something slightly different.

• Słychać dzieci. = You can hear the children.
• Słychać śmiech dzieci. = You can hear the laughter of children.

The version with śmiech is more specific: it tells you exactly what kind of sound is coming from the kitchen.

Usually, yes, that is the natural implication. If you can hear children’s laughter, it normally means children are laughing at that moment.

But grammatically, the phrase itself is a noun phrase, not a full verb phrase. It literally names the sound:

• śmiech = laughter
• dzieci = of children

So the sentence describes what is audible, rather than directly saying the children are laughing.

Yes, very natural.

A Polish speaker would commonly use this kind of structure to describe sounds:

• Z pokoju słychać muzykę. = Music can be heard from the room.
• Z ulicy słychać hałas. = Noise can be heard from the street.
• Z kuchni słychać śmiech dzieci. = Children’s laughter can be heard from the kitchen.

It sounds idiomatic and normal in everyday speech and writing.