Planespeech

Also called "zuctus" this language is mainly spoken by Retari in their relatively secluded journeys through the 13 different material planes. Described as a very practical, yet hard to learn and diverse language it offers different pronounciation, or even forms of sign language to accomodate the vastly different circumstances Retari face when travelling the plains.
Often used by planediving mages it is a powerful tool in any palanamncers toolbox, especially since inetlligent life from other planes will most likely speak zuctu rather than common.