Victor Mair has an interesting post at the Log about an article (in this 2008 book) by Tibetanist Nicholas Tournadre in which Tournadre says that there are 220 “Tibetan dialects” derived from Old Tibetan:
In a forthcoming work, Tournadre states that these “dialects” may be classed within 25 “dialect groups,” i.e., groups that do not permit mutual intelligibility. According to Tournadre, the notion of “dialect group” is equivalent to the notion of “language,” but does not entail standardization. Consequently, says Tournadre, if the concept of standardization is set aside, it would be more appropriate to speak of 25 languages derived from Old Tibetan rather than 25 “dialect groups.”
This fascinates me; does anyone know how controversial it is?