You don't use it when you are trying to say you don't know something, but you can use it as an answer to a question. Q. What is that thing? A. Saa (dunno) My

You don't use it when you are trying to say you don't know something, but you can use it as an answer to a question. Q. What is that thing? A. Saa (dunno) My guess is that the Italian "boh" is the same.