Yashuvhi was the native language of the Yashuvhi people, Human settlers from Yashuvhu.
Yashuvhi was a derivative of Basic language, although using inflections instead of prepositions. This could be because Yashuvhu was a Human settling which had lost contact with the galaxy, or because, millennia ago, an unidentified Jedi crashed on Yashuvhu and became an important member of the community (The word "Jedi" was used with an almost religious fervor).
First-contact specialists on Pathfinder III could easily learn the basics of Yashuvhi when they re-discovered the world on 33 BBY.