It is not a uniform speech, but comprises several dialects which have been classed by Jaeschke into three groups, namely (i) the central or the dialects of Lhasa and the central provinces of U and Tsang (including Spiti) which is the lingua franca of the whole country, (2) the western dialects of Ladak, Lahul, Baltistan and Purig, and (3) the eastern dialects of the province of Khams. In addition to these, however, are many sub-dialects of Tibetan spoken in the frontier Himalayan districts and states outside Tibet, namely, in Kunawar and Bashahr, Garhwal, Kumaon, Nepal including especially the Serpa and Murmi of eastern Nepal, Sikkim (where the dialect is called Danjong-ka), Bhutan (Lho-ka or Duk-ka.), all of which are affiliated to a central group of dialects.
It was at this stage that the language spread in Lahul and Spiti, where the superscribed letters were silent, the d and g finals were hardly heard, and as, os, us were ai, oi, ui.
Spra or spreu (a monkey), now altered into deu at Lhasa, teu in Lahul, Spiti and Tsang, is still more recognizable in the Gyarung shepri and in the following degenerated forms - shreu in Ladak, streu-go in Khams and in cognate languages, soba in Limbu, saheu in Lepcha, simai in Tablung Naga, sibeh in Abor Miri, shibe in Sibsagar Miri, sarrha in Kol, sara in Kuri, &c. Grog-ma (ant), now altered into the spoken t'oma, is still kyoma in Bhutan, and, without the suffix, korok in Gyarung, k'oro- in Sokpa, k'orok, k'alek in Kiranti, &c. Grang-po- (cold), spoken t' ammo, is still grang-mo in Takpa, k'yam in Burmese, &c. A respectful word for " head " is ii, written dbu, which finds its cognates in Murmi thobo, Sibsagar Miri tub, &c. Bya (bird), spoken cha, is still pye in Gyarung.
For instance, gye (eight), which is written brgyad and still spoken vrgyad in Balti in the west and Khams in the east, is gyod in Ladak, Lahul, Tsang and U.
The greater part of the remainder are found in Bengal on the borders of Burma, on the borders of Nepal, Tibet and Bhutan, and in the Spiti, Lahul and Kanawar districts of the Punjab Himalayas, where many of the inhabitants are of Tibetan origin.