 Somerville was born in Iowa City, Iowa, to Lefa Mary (née Pash; 1918–2011) and the Rev.Paul Somerville (1919-1995), who moved the family around as he preached at different parishes, until settling in Traer, and eventually Cresco, Iowa.There, her mother worked as a librarian and Phyllis attended high school, where she was involved with cheerleading, drama, and music, including playing clarinet in the All-State band.