Linguistic diversity in Greater Tibet

Arif Dirlik called my attention to a wonderful article entitled "'Speak Tibetan, Stupid': Concepts of Pure Tibetan & the Politics of Belonging" in the Lhakar Diaries.

At the heart of the article is this powerful 16 minute video entitled "Linguistic Diversity on the Tibetan Plateau":

The large number of Tibetan languages and bewildering variety of languages from other groups are strikingly demonstrated in this clear video presentation.

What are the implications of this obvious linguistic diversity within Tibetan for our understanding of the linguistic diversity within the Sinitic group / family of languages and their classification? This is a conundrum of large proportions that we have often grappled with on Language Log, e.g., "Is Cantonese a language, or a personification of the devil?" (with links to other posts and resources; see especially here, here, and here and this chapter on the classification of Sinitic in the Festschrift for Alain Peyraube).

Since the video takes time to view and because the questions it raises are so numerous and substantial, I will refrain from discussing it at greater length here, but I do hope for a lively discussion on the nature and classification of Tibetic and Sintic languages.

N.B.: The number of Tibetic speakers amount to approximately 8 million (plus 200,000 or so in exile), yet they are divided into so many different languages and dialects; the number of Sinitic speakers amount to roughly 1.3 billion, yet politically minded partisans insist that there is only a single Sinitic language and that all of its countless varieties, even those that are mutually completely unintelligible, are but dialects of it.