At the age of 13, he was legally adopted by his stepfather, who was Polish, and took on the surname Wilimowski. At home, he spoke German for the most part, while in public he often spoke a Silesian dialect of the Polish language. Officially a citizen of Poland, he referred to himself as an Upper Silesian ("Górnoślązak" - Oberschlesier).
When he was 13, he was formally adopted by his stepfather, who was of Polish descent, and took on the surname Wilimowski. In his family home, German was the predominant language spoken, whereas in public settings, a Silesian dialect of Polish was commonly used. As an officially recognized citizen of Poland, he identified himself as an Upper Silesian ("Górnoślązak" - Oberschlesier).