Kolorowa piłka leży na boisku.

Because Polish adjectives must agree with the noun they describe in gender, number, and case.

• piłka is a feminine singular noun.
• So the adjective kolorowy changes to its feminine form: kolorowa.

That is why you get:

• kolorowa piłka = colorful ball

If the noun were masculine, you would use kolorowy instead.

Piłka means ball.

It is a common Polish noun used for many kinds of balls, for example:

• piłka nożna = football / soccer ball
• piłka tenisowa = tennis ball

In this sentence, piłka is just a ball.

Because after na in this sentence, Polish uses the locative case to express location.

The basic form is:

• boisko = field / sports ground / playing field

But after na when meaning on or at a location, it becomes:

• na boisku = on the field / on the sports ground

So:

• boisko = dictionary form, nominative
• boisku = locative singular

This kind of change is very common in Polish.

Not always. Na can take different cases depending on the meaning.

In this sentence, na shows location, so it takes the locative:

• na boisku = on the field

But when na shows movement toward a place, it often takes the accusative:

• Idę na boisko. = I’m going to the field.

So a useful rule is:

• location → often locative
• motion toward → often accusative

Leży means lies or is lying.

It comes from the verb leżeć, which means to lie or to be in a lying position.

So the sentence suggests that the ball is lying on the field, not just existing there in a neutral way.

Compare:

• Piłka leży na boisku. = The ball is lying on the field.
• Piłka jest na boisku. = The ball is on the field.

Both can work, but leży gives a more physical image.

Polish usually does not use articles like English a or the.

So:

• piłka can mean a ball or the ball
• the exact meaning depends on context

That means Kolorowa piłka leży na boisku could be understood as:

• A colorful ball is lying on the field or
• The colorful ball is lying on the field

Polish leaves that distinction to context.

The sentence uses a very natural and neutral Polish word order:

• Kolorowa piłka = subject
• leży = verb
• na boisku = place expression

So it is basically:

• Colorful ball lies on field

Polish word order is more flexible than English because case endings show grammatical relationships. For example, you could also say:

• Na boisku leży kolorowa piłka.

This puts more focus on where the ball is.

Both are correct, but the original sentence is a simple, neutral version.

A rough English-friendly guide:

• piłka ≈ PEEW-ka
• boisku ≈ bo-EES-koo

A few useful sound notes:

• ł is pronounced like English w
• pi before a vowel sounds softer, somewhat like pyi
• oi in boisku is pronounced separately, not like English oy

So:

• piłka sounds closer to peew-ka than pill-ka

Not necessarily. Boisko usually means a sports field, playing field, or court, depending on context.

It can refer to places used for sports such as:

• football / soccer
• basketball
• volleyball
• school sports grounds

So na boisku is best understood broadly as on the playing field or on the sports ground unless the context makes the sport clear.

Yes. That is correct Polish.

• Piłka jest na boisku. = The ball is on the field.
• Piłka leży na boisku. = The ball is lying on the field.

The difference is that jest is more neutral, while leży describes the ball’s position more vividly.

Since a ball normally rests by lying somewhere, leży sounds very natural here.

It is in the nominative case because it is the subject of the sentence.

You can see that both words are in nominative singular feminine:

• kolorowa = nominative singular feminine adjective
• piłka = nominative singular feminine noun

So the structure is:

• Kolorowa piłka = the subject
• leży = what it is doing
• na boisku = where it is

Yes, kolorowa is a normal and natural translation of colorful.

It suggests that the ball has multiple colors or a bright, colorful appearance.

The base adjective is:

• kolorowy = colorful

And here it changes to kolorowa to match the feminine noun piłka.