my son is 6mths also and i notice he has very good memory. he remembers songs that i switch up on him daily. when i start sing a song and he looks and gives me a big smile i know he remembers it so if he has memory he can learn..i say start sing the ABCs and do some clapping singing number 1-10. even make a song out of the babies name so you can start with these three things to get his memory going.