Na podwórku nie ma nikogo.

Na podwórku means in the yard / in the courtyard.

The noun’s base form is podwórko. After na when you are talking about location, Polish normally uses the locative case, so:

• podwórko → podwórku

So this is:

• na podwórku = in/on the yard/courtyard

Even though na often literally means on, with places it can simply mean in/at.

This is mostly a matter of normal Polish usage.

With open areas or certain locations, Polish often prefers na rather than w. A yard/courtyard is typically said as:

• na podwórku

not usually:

• w podwórku

So even if English says in the yard, Polish idiomatically uses na here.

This is one of the most important patterns in Polish.

To say that something exists somewhere, Polish often uses:

• jest / są in affirmative sentences
  
  • Na podwórku jest pies. = There is a dog in the yard.

But in negative existential sentences, Polish normally uses:

• nie ma = there isn’t / there aren’t

So:

• Na podwórku nie ma nikogo. = There is nobody in the yard.

Using nie jest here would not sound right, because jest is not normally negated this way for simple existence.

Because nikogo is the form required by nie ma.

The base word is:

• nikt = nobody / no one (nominative)

But after nie ma, Polish uses the genitive, so:

• nikt → nikogo

Compare:

• Nikt tu nie mieszka. = Nobody lives here.
• Tu nie ma nikogo. = There is nobody here.

So in your sentence, nikogo is correct because nie ma calls for the genitive.

Because Polish uses negative concord.

In English, standard double negatives are usually avoided, but in Polish they are required in sentences like this. If you use a negative word such as:

• nikt / nikogo = nobody
• nic = nothing
• nigdy = never

the verb is also negative:

• Nikogo nie ma.
• Nic nie wiem.
• Nigdy tam nie chodzę.

So nikogo nie ma is not bad grammar in Polish — it is the correct grammar.

The word order is fairly flexible.

Your sentence:

• Na podwórku nie ma nikogo.

is natural and correct.

You could also hear:

• Na podwórku nikogo nie ma.
• Nikogo nie ma na podwórku.

These all mean basically the same thing, but the emphasis changes a little:

• Na podwórku nie ma nikogo. — neutral
• Na podwórku nikogo nie ma. — slightly more emphasis on nobody
• Nikogo nie ma na podwórku. — stronger focus on nobody

Polish often moves words around to highlight different parts of the sentence.

In this construction, nie ma stays the same.

Polish uses nie ma as a fixed existential negative pattern, regardless of whether English would say isn’t or aren’t.

For example:

• Na podwórku nie ma nikogo. = There is nobody in the yard.
• Na podwórku nie ma dzieci. = There are no children in the yard.
• Na stole nie ma książek. = There are no books on the table.

So you do not change it to a plural form here.

Podwórko usually means a yard, courtyard, or the open area around/between buildings, especially near a house or apartment building.

Depending on context, English translations could include:

• yard
• courtyard
• backyard
• sometimes just outside area

So the exact English word depends on the situation, but yard/courtyard is a good general meaning.

Yes, in practice it often matches either English version:

• There is nobody in the yard.
• There isn’t anybody in the yard.

Both are natural translations of:

• Na podwórku nie ma nikogo.

Polish uses a negative pronoun here, while English can choose between nobody and anybody after negation.

A simple pronunciation guide is:

• Na podwórku nie ma nikogo
• nah pod-VOOR-koo nyeh mah nee-KO-go

A few helpful points:

• ó is pronounced like Polish u
• nie before a consonant sounds roughly like nyeh
• stress in Polish is usually on the second-to-last syllable:
  • podWÓRku
  • niKOgo

So the rhythm is roughly:

• na pod-WÓR-ku nie ma ni-KO-go