In a January 2013 New York Times Magazine profile, Mamet said that her first name is pronounced ZAH-shah ("like Sasha with a Z").
Zosia's father is Ashkenazi Jewish (from a family from Russia and Poland). Zosia's mother has English, Scots-Irish (Northern Irish), German, and Welsh ancestry.
Her name pronounced as "ZAW-shah". It's nickname of Polish-Greek name Zofia meaning "wisdom".