Galach

Galach is the universal language in the Dune universe, Inglo-Slavic in origin (essentially, it is descended from English and Russian). Galach is the official language of the Imperium and is used in official texts and in the Royal Court on Kaitain. Other langauges are used at a local level and many people will only use Galach when they meet a person from another planet. In this way Galach serves as the Lingua Franca of the Dune Universe.

It also appears as the universal language in other novels by Frank Herbert such as The Whipping Star and The Dosadi Experiment.