In Harry Potter and the Methods of Rationality, they explicitly talk about the Pseudo-Latin as a way to control magic. I've also noticed Greek, as in:
Spoilers, Chapter 111
When Voldemort is performing the ritual to revive Hermione, the obelisks speak this chant: "Apokatastethi, apokatastethi, apokatastethi to soma mou emoi." With some Google Translate magic, this appears to be: "Aποκαταστήσει, αποκαταστήσει, αποκαταστήσει to σώμα μου εμοί", which means "Restore to me my body" or something similar. I don't speak Greek, so excuse any crudeness here.
What other incantations have been used that are in an alternate language?