Honestly? My parents rarely told me I "couldn't" use a word (they were far more likely to tell someone else to speak to me like an adult - baby talk was strictly verboten in my house) They often asked me to be more articulate, to explain why I was frustrated, but that just gave me the biggest vocabulary of anyone I knew and impressed every teacher I ever had. Only word I remember they were really upset abpit was a substitution - frig (you can guess what I was substituting it for) - and I had no idea why until I looked up the actual meaning, and discovered the victorian pornographic usage (this would have been when I was 9 or so). whoops. I didn't use it much after that, unless I felt like pissing them off.