Los Angeles-based actor Dale Dymkoski has a lot in common with Billy, the character he portrays in Vermont Stage’s season-opening production of Tribes. Dymkoski was born with severe hearing loss and Billy was born deaf; neither learned sign language as a child. For fictional Billy, that means existing on the periphery of his clan’s dynamics, isolated by the language barrier, until he meets a young woman who helps him find his own voice. Performers in this Nina Raine-written comedic drama use both English and American Sign Language to tell a story that the New Yorker calls “as much about the tyranny of language as it is about the misery of not being able to hear it.”