Thank you for providing me with your background. Sesame Street has always been a great show to watch but since your child has already been watching television shows then I would like to suggest an alternative. Excellent and child friendly educational software for children from infants on up are the programs by Jumpstart...the publisher is Knowledge Adventure. There is one specifically called Jumpstart Preschool and another called Jumpstart Preschool Advanced. Your children will learn English as pre reading, letters, shapes, numbers, colors, differences, sequencing, counting, qualities, spatial relationships, listening skills, music, vocabulary, and phonics are addressed.
Another more advanced and much more expensive software program is the Rosetta Stone for kids. This would be better for your child when he/she start regular school as it is a little more advanced but you could still check out level 1. Also children's literature books that are accompanied by a CD that goes with the story are also excellent when played several times so that the English language can be heard.
Hope these suggestions help. Have a great day!!!!