Polish? That is impressive. German and English are fairly easy for a swede, being germanic languages and all. But polish, yeah that is impressive.
What is true is that his language skills were first used in union organizing activities and later in Minnesota to help organize agricultural coops. I never found out if could ever write in Polish, but he could whip a crowd into a political frenzy in Polish. That may not fit the classic definition of "fluent" but it is close enough for me. His neighbor claimed he had a noticeable Swedish accent when he spoke Polish but that no one had trouble understanding him. "Remember the I35W bridge--who needs terrorists when there are Republicans"