Polyglot

This pseudo-language is more of a natural ability or something gifted by a deity or powerful artifact. A Polyglot character is able to learn new languages extremely quickly, and can mostly function in a new language in real time as the conversation goes on. Only a few people possess this ability, but they serve as powerful translators and diplomats. Some are even able to retain any language they learn, and build vast libraries of linguistic structures in their minds.

Polyglot is included in the Gether Guide to Languages on DrivethruRPG:
https://www.drivethrurpg.com/product/328473/Gether-Guide-To-Languages