It was cute and funny at first that both of us were being called Mommy, and I still don't really mind. My wife and I laugh and try to correct him, pointing to pictures, ourselves and repeating the correct words.
My 21m toddler is just starting to talk, so it's probably normal to be confused a bit, but this confusion is really starting to solidify; I got home from work last night and my boy's face lite up and he repeatedly exclaimed "MOMMY!" several times pointing to me and gibbering to my wife, seemingly explaining to her that I was home. The word Mommy is now more for me than my wife.
Has anyone heard of something like this? Maybe we set him on the wrong track by laughing at the confusion in the beginning; he probably liked the reaction.