As I move farther away from World Canonical Texts and Humanities, what interests me more is "what languages do Harvard's Ph.D. in Social Science require?" Below are the requirements for the following departments, based on the Graduate Handbook.
Economics - no language requirement (meaning just English is good enough!)
Government - "research tool" requirement: "a minimum of 3.5 half-course-equivalent units", for which "Students may count language training in various formats (e.g. semester courses; intensive summer sessions) toward fulfillment of this requirement."
Health Policy - no language requirement
History of Science - proficiency in one language other than English, "Students can demonstrate proficiency in various ways, but most often by taking third-year coursework in a language other than English"
Political Economy and Government - no language requirement
Psychology - no mention of language requirement
Sociology - no language requirement
So it turns out that for Social Science, the only departmental Ph.D.s that require foreign languages are Anthropology, History of Science, together with History and African & African American Studies.