Very weak literature without evidence is presented by some authors until now claiming that they are the Kirats.
They adopted some cultural and religious practice from Sunuwars and Sherpas when they began to live and share with them.
Their physical appearance and family name are also supporting evidence for Tibetan origin.
They also have Shamans who are called Phombo, which is derived from the word, Boo, the Tibetan Tantric philosophy.
The script is shown below: ཀ ka [ká] ཁ kha [kʰá] ག ga [ɡà/kʰːà] ང nga [ŋà] ཅ ca [tɕá] ཆ cha [tɕʰá] ཇ ja [dʑà/tɕʰːà] ཉ nya [ɲà] ཏ ta [tá] ཐ tha [tʰá] ད da [dà/tʰːà] ན na [nà] པ pa [pá] ཕ pha [pʰá] བ ba [bà/pʰːà] མ ma [mà] ཙ tsa [tsá] ཚ tsha [tsʰá] ཛ dza [dzà/tsʰːà] ཝ wa [wà] ཞ zha [ʑà] ཟ za [zà] འ 'a [ʔà] ཡ ya [jà] ར ra [rà] ལ la [là] ཤ sha [ɕá] ས sa [sá] ཧ ha [há] ཨ a [ʔá] The similarity of Jirel language that with the language used in Buddhist holy books is the powerful evidence to claim and believe that they are of Tibetan origin.