I can't

My 2 year old son's new favorite expression is "I can't". Actually it is "I tan't" because he really can't make the sound "c". Today he sat down on the kitchen floor and took off one shoe. Then he pleaded with me to take off his other shoe "help, I tan't".

When I said "No, you can do it."

He scootched himself over to his 11 month old sister and said "Baby do it?"