Here's my review of the Malayalam movie "Su Su Sudhi Vathmeekam", which is based on stammering.

Indian Cinema has traditionally seen stammerers (PWS) as
comic characters. Lately, there were protagonists who stammered… But a
Malayalam film - Su Su Sudhi Vathmeekam comes as a fresh air, which revolves
around a person who stammers and is probably the first Indian film that is primarily
about stammering.