I believe the number of "dialects" named in My Fair Lady can be largely explained by the lack of clear distinction between language and dialect over the years. From [1]: "There is no universally accepted criterion for distinguishing a language from a dialect. A number of rough measures exist, sometimes leading to contradictory results. The distinction is therefore subjective and depends on the user's frame of reference."

Getting upset about Henry Higgins's estimation of the number of Indian "dialects" in a play from many decades ago doesn't make sense to me. His character was deliberately portrayed as a regressive lout, and terminology has surely changed in the intervening years.

[1]: http://en.wikipedia.org/wiki/Dialect#Dialect_or_language