We have copies of Wilhelm Gottlieb Julius Lueck's baptism (December 1873 in Pulaski, WI) and confirmation (April 1889 in Muscoda, WI) and the forms are partially in German. His last name was spelled Lueck on those forms then. He changed his name to William Leek on the August 1900 marriage forms (which are also partially in German) when he married Elizabeth Lischsky in Pulaski, WI. He died in 1924 when my husband's father was 7 so we have very little information about his background and family tree.
I think that some of my husband's other relatives (Ohms, Wolfgramms and perhaps the Bussas) came from Pommerania which I understand was part of Prussia and now part of Poland.