Give me 11 year old Remus Lupin with a stammer.
Give me little boy who can barely get one sentence out without tripping over and stopping after every word.
Give me a scarred boy who is so nervous in the new school he avoids talking to everyone where possible.
Give me Remus Lupin with a really bad stammer in classes, meals and social interactions.
Then give me a Remus Lupin minding his own business in the boys dormitory, who then stubs his toe badly on the bed post.
Give me an 11 year old boy with a stammer who lets out the most eloquent, coherent and violent string of curse words one has ever heard.
No stammer, just air turned blue from all the swearing.
Then give me the most shocked slow clap ever from one Sirius Black and James Potter.