I bought this for my son when he was about 15 months old. We had a 30 minute commute home from daycare after I got out of work, so I wanted to find him something educational that he could play with during the long drive. I knew it was a little old for him, but thought he would enjoy it anyway, even if he was not going to get too much out of it. Unbeknownst to me, he flourished with this LeapTop. He learned his letters, their sounds, and words associated to all of the letters of the alphabet within 6 months. He is still not even 2 years old yet, so I guess we'll start teaching him to read next. :-)
He learned these things without us even noticing, for the most part. We really realized how much of an influence it had on him when we began teaching him the letter sounds, since he had learned his alphabet by 18 months. He picked up the letter sounds extremely fast, and then unprompted, began to tell us words that started with these letters. When he started mentioning words that we would never have said to him, such as "Newt", we realized that he had picked these up from the LeapTop. Incredible toy! If I could give it more stars, I would.