Telepathy

Telepathy is a form of communication that is completely done in the mind - one mind linking to another, or to multiple others, to speak and be understood without having to use spoken words or physical gestures.

This magic is wonderful for many purposes, most notably connecting when individuals do not share a language and of course for covert missions of any sort. It often has a limited range, however, and those that don't have a very short limit on how long the spell will last which means messages have to be quick and efficient.