Yes, this is Riz Ahmed’s showcase and his ultimate moment, thus far. But, excellent performances abound. Paul Raci, a CODA (Child of Deaf Parents), as the director of the group home builds a portrait of a seasoned counselor who is as transparent and nurturing as he is demanding and disciplined. Lauren Ridloff (TV’s The Walking Dead), a former Miss Deaf America, enlivens the role of Diane, a congenial elementary school teacher. Mathieu Amalric (Munich) as Lou’s dad casts a very paternal shadow. While Oliva Cooke perfectly counterbalances Ahmed.