Hi, when I say 'pardon' to my young son (3 years old) because I either have not heard him or am not sure if I heard correctly - he tells me "mummy we say 'what' not pardon, thats what our teacher tells us."
Can you tell me if this is correct before I go in and speak to them about it!!
Before marching into the classroom to correct the teacher, please be aware that the use of 'what' in the situation you describe is definitely common usage in North America. You will beat your head against the wall if you expect the teacher to change what is universally accepted.
I, personally, prefer the more polite response of 'pardon' when I indicate that I didn't hear or understand the speaker's comment.
You might explain to your son that, while 'what' may be used in such situations, you would prefer that he use the more polite 'pardon'. Continue to role model the use of 'pardon' when your son is with you.
However, having said this, you will have to accept the fact that a 3 year old boy who says 'pardon' instead of 'what' may be looked upon as being a little strange by his companions.