Simplify the following text for a Grade 6 native English-speaking person.
Original: The influence of Chicago 's Polish community is demonstrated by the numerous Polish-American organizations : the Polish Museum of America , Polish American Association , Polish American Congress , Polish National Alliance , Polish Falcons and the Polish Highlanders Alliance of North America .
Simplified: A Polish American is a citizen of the United States with ancestors from Poland . There have been Polish people living in North America since the earlier 1600s .