It was a slang or jargon of traders and spacers. That way, it spread throughout the galaxy and others, non-spacers, also learned it in order to be able to communicate with other species; eventually it was adopted officially as the language of Coruscant and the Galactic Republic.
It was the precursor of Mid-Galactic Standard and Galactic Basic Standard, and was still in use as of the Pius Dea Era. Arden Lyn and Halbret were speakers of this language. By the time of the Dark Wars, Jedi Master Atris could still speak it.