When I worked for Kaplan test prep we "auditioned" teachers, asking them to teach any topic for 5 min. One candidate was great, but had a thick accent. One of the managers made the mistake of telling him we would not proceed because of the accent. He sued because of discrimination based on national origin and Kaplan settled for about $100k.
When I left my old company as director of engineering I recommended one of the team as my replacement but the CEO declined, saying there were "communication issues" (the team member is deaf). I told him what the CEO had said and recommended he sue. They also settled out of court.