Primordial Language

Primordial was the language of primordials and elementals. Almost nothing would be described as simply speaking "Primordial" as it is considered more of a language family rather than a distinct tongue. The elemental languages Aquan, Auran, Ignan, and Terran were considered a group of dialects of Primordial. They were sufficiently similar that creatures who understood one of those dialects could understand the others as well.
Aquan was the language of the Elemental Plane of Water. It was a flowing language full of subtleties of meaning.
Auran was the language of the Elemental Plane of Air. It was a breathy, relaxed language that has been described as a slow exhaling of air.
Ignan was the language from the Elemental Plane of Fire. It was a language full of sharp clicks and hisses.
Terran was the language of creatures from the Elemental Plane of Earth or those otherwise related to the earth in some way. Terran is a rumbling language with deep tones that reverberate through the listener.