>>24638582 (OP)
On real philosophy syllabi there are only two philosophers who wrote in Latin in the top 100, and they are way, way down the list. There are also only two who wrote in Greek, although they are at least high on the list. No other Greek has more than the most marginal of presence.
German would at least make a bit more sense. French would make more sense though, since Foucault, Derrida, and Deleuze are pretty huge across all fields.
The image of philosophy as involving Greek and Latin is wholly outdated. Daniel Dennett or David Chalmers is more popular than Aquinas or Augustine. Start with the Americans.