Tourette Syndrome in popular culture is often simplified to a poorly timed foul mouth, but that’s only a small part of the story—or sometimes not part of the story at all.

AS EMILLY Carter finishes her song, the only thing that’s noticeable about her singing is that it’s very, very good. It’s only after the music stops that Emilly’s tics become apparent. Sniffing, coughing and touching her nose, Emilly has...