Re: Diglossia and Bilingualism--Social Class & Conquest
The classic instance of diglossia in English may have occurred in the period following the Norman conquest of England, during which time a ruling class that increasingly spoke a mixture of French and English among themselves also communicated with "commoners," who discoursed in Old English/Middle English in their millieu and often never learned French. This former 'diglossic' condition has contributed to the richness of English, in terms of words, so that mutton is the Frankish form of sheep, the first emanating from the tables that served it, the second resulting from the usage of those who tended and killed the animals. Similarly, beef is the food form of cattle.
Robert Graves, in his "The Reader Over Your Shoulder," suggests that almost all imperial languages--such as Mandarin Chinese, Spanish, Turkish, Arabic, and English, not to mention Latin and Greek--have developed in this dialectical way. Conquest leads to a bifurcation from which diglossia inevitably results.