Kulung Rai is one of the Rai languages. It belongs to the Tibeto-Burman language family. According to the census (2001), the population is around 18,686. Most of this people group is located in the Solukhumbu, Sankhuwasawa, Terhathum, Panchtar and Ilam districts.

Kulung orthography was drafted by a linguist in early 1970. The Kulung language committee further developed it. Now it is widely used in this language group.