I believe that it depends on the graduate students' interest and research inclinations. For example, if one would like to do research on Philippine history, then one might need to learn Spanish to understand written history written in Spanish. If one dreams to work in Germany in the future, then studying German will be beneficial. Hope that helps.
Thank Joana. Indeed, language related to subject is most practical. Apart from Spanish, I would also promote learning foreign languages such as French, German, Russian, Japanees, Korean, plus more.