I have a good friend who was born in the US to a Polish mother and spoke alot of Polish as a child.

When she was in her 20s, she went to Poland with her mother, and she got a stomach virus. Her mom took her to the doctor, and the doctor asked her how she felt, and my friend, knowing only child-Polish, said something like, "My tummy-wummy hurts!"

Everyone had a good laugh over it. She works in international development and does put Polish on her resume, but does not claim to be fluent.