No, no, baby talk is a GOOD thing! Maybe at this stage it is too late for it to help, (I'm not a language expert yet, so I don't know) but any speech therapist who tries to tell you that baby talk is bad for your child is outdated in the extreme.
He has to have verbal stimuli that is simple enough for him to process in order to learn it. Imagine walking into an upper-division Spanish class without being exposed to any instruction. A child has to learn how to speak his or her language without any help or translation; it's the least we can do to make it easier on them.