Judith is known for her work in Sephardic music, and related traditions. Her ethnomusicological work and her life as a performer are intertwined. Village songs of Spain and Portugal, narrative ballads and stories in English and pan-European traditions, Balkan singing, songs of French Canada, Yiddish - and music of Medieval Europe are among her performance and workshop repertoires, and as an ethnomusicologist, besides her signature work in Sephardic music, she is known for her many years of fieldwork and research on music in the lives of  Portuguese Bnei Anusim, often known as Crypto-Jews, direct descendants of the Jews who maintained their identity throughout the centuries of the Inquisition. She is the consultant for the Spanish Recordings (1952) of the legendary Alan Lomax collection, and is preparing an edition of Lomax's Spain diary with her own follow-up fieldwork for the University Press of Mississippi.

Judith accompanies her singing and storytelling on traditional frame drums of Spain, Portugal and North Africa, on the medieval bowed vièle, Appalachian mountain dulcimer and other instruments; she also performs on and teaches recorders, in both Early Music and folk traditions. She teaches part-time at York University in Toronto, and gives guest talks, performance-talks, workshops and concerts, solo or with one or more musicians.