My son began watching this around 18 months of age. He wasn't yet able to pronounce the parts of the trucks that Leo builds during the show. Now, at 21 months, he says almost all of the parts very clearly! He is even pointing out parts like "front bumper" on his own toy trucks and cars. This is a great show for language development and learning to categorize and generalize that is simple in design animation and has developmentally appropriate content. Love it!