Definition of "isolect"

Dohoi is distinctive among all the Barito isolects […] .

1967, Alfred B. Hudson, The Barito Isolects of Borneo: a Classification Based on Comparative Reconstruction and Lexicostatistics, page 53

At the same time, the ordering of isolects that is finally chosen must give the right results for (virtually) all the environments.

2003, Ralph W. Fasold, The Sociolinguistics Of Language, page 200

While Middle Malay, Minangkabau, and Kerinci have inland and west coast variants as their origin, Malay itself developed from isolects spoken on the east coast.

2008, Keith Brown, Sarah Ogilvie, Malay, entry in Concise Encyclopedia of Languages of the World, page 677