Polish demonstratives agree with the noun’s gender and number:
Since piłka is a feminine noun, you must say ta piłka, not ten piłka or to piłka.
Piłka is pronounced approximately like PEEW-ka:
IPA: [ˈpʲiw.ka]
The stress is on the first syllable: PIŁ-ka.
No. Polish does not use articles like a/an or the.
Definiteness is usually shown with demonstratives like ta / ten / to, context, or word order, not with a separate article.
You need jest (the 3rd person singular of być – to be) to make a proper sentence like English is:
Saying Ta piłka nowa is not standard; it sounds incomplete or like a fragment.
Polish normally uses jest in such X is Y statements.
Both piłka and nowa are in the nominative singular feminine:
In [noun] jest [adjective], both parts are nominative.
The neutral, most common order is:
Other orders are possible, but they change emphasis:
For everyday speech when you just state a fact, stick to Ta piłka jest nowa.
You need plural forms for this, ball, the verb, and the adjective:
Breakdown:
Both can be translated as This is a new ball, but they focus on slightly different things:
Ta piłka jest nowa. – literally This ball is new.
To jest nowa piłka. – literally This is a new ball.