<p>You only need a reading knowledge of the relevant scholarly languages. You possibly could pick these up through self-study, a graduate reading course (after admission to grad school or in summer school)—it doesn’t take a minor. I would recommend that you check the specific requirements of graduate art history depts that interest you. That’ll give you a better idea of what emphasis they place on languages in the admission process, but I suspect an applicant with languages may have an advantage.</p>