Hi okhud!
This makes perfect sense. It's wonderful that your little one is becoming more verbal thanks to Little Reader. Yay!
Actually, I have a friend who is a speech pathologist and one of her recommendations is to have your child hear the word you want to teach them over and over in as clear a tone as possible. You may notice children repeat words that a doll says after a child repeatedly presses the button to make it say something, the same goes with books that have sound buttons. I like that Little Reader is simplistic in its approach. It is what makes LR very powerful in teaching. Not too many decorations, not too much fluff that can be distracting.
Aw that's cute that he tries to whisper the word. He may be testing it out before he starts openly saying it. My little one was like that. I would catch him trying out the word when he thought he was alone and nobody was watching,