Knock knock

Liem used to say "Eee eee" when knocking on doors or windows. He's finally learnt to say "knock knock".

Not entirely clear on the concept of knock knock jokes though...

Liem: Knock knock
Mummy: Who's there?
L: Mummy
M: Mummy who?
L: Knock knock
M: Who's there?
L: Mummy!
M: Mummy who?
L: Knock knock...

L: Knock knock
M: Who's there?
L: Calf
M: Calf who?
L: Stuck!