Even more bizarre than worrying about swearing, I once had a 911 dispatcher understand the street I was saying, but stop to correct my pronunciation. I had just moved to a new house and my roommate had injured himself. I called 911 and when I told them my address was "123 foobar" the dispatcher responded, "actually it's pronounced 123 foobaz". A long awkward silence followed which I eventually broke with a simple "ok". I really didn't know what else to say.

Correcting my pronunciation of a street name is fine in most contexts, but it seems like an awfully trivial thing to spend time on while my friend is bleeding profusely.