Sociolinguistics
Fishman's (1967) Concept of Diglossia
Joshua Fishman presented a modification of Ferguson’s (1959) original concept and rather strict definition of diglossia in 1967. He proposed an expansion of Ferguson's definition of diglossia in two respects:
(1) A diglossic speech community is not characterized by the use of two language varieties only. There may be more than two language varieties used within a diglossic community.
(2) According to Fishman (1967), diglossia refers to all kinds of language varieties which show functional distribution in a speech community. Diglossia, as a consequence, describes a number of sociolinguistic situations, from stylistic differences within one language or the use of separate dialects (Ferguson’s ‘standard-with-dialects’ distinction) to the use of (related or unrelated) separate languages.