Ruga language
Ruga is a Garo dialect, an Sino-Tibetan language that spoken in the East Garo Hills district and West Garo Hills, Meghalaya, India. Today, people who identify themselves as Ruga have shifted to Garo and only a few elderly native Ruga speakers remain. Ruga Tribe 
Ruga people identify as a sub-tribe of a GaroTribe. Ruga people have their own distinct identity. Ruga language shares similarities with other Garo languages. It is closely related to Atong language (Sino-Tibetan) and Koch language.Ruga speakers have lost their language and hence, they have shifted to Am·beng dialect. They mostly reside along the valleys of Bugai River and in Rugapara areas of Gasuapara block under South Garo Hills. References

Sal languages
Extinct languages of Asia
Languages of India
Languages extinct in the 21st century