Alomst there...

This is how the ABC's go in his head:
ABCDE-UP- GHIK-KLMNO-MENO-MENO-PQRSTUVWXYZ!

And the numbers go something like this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 17 18 19 20 21 22 23 21 22 23... 16 does not exsist and he just will go on and on with 21 22 and 23.

I try not to laugh when he sings his ABC's, but it really is precious the way he does it.