Universal translator

A universal translator translated any language in the universe heard or spoken by the person who used one.

They were used by some space-faring humanoids like the Muxteran, given their MediPods could implant one if someone being healed by it didn't have one. (TV: The Ghost Monument)

Valarie Lockwood was fitted with a universal translator, rendering the TARDIS's translation circuit redundant. (AUDIO: The House of Masks)