The Cambridge History of English and American Literature in 18 Volumes (1907–21).
Volume III. Renascence and Reformation.
§ 2. Elizabethan English
Of changes in pronunciation during the fifteenth century, those of open and close 
and 
, are, perhaps, the most important. The open and close values had, apparently, been distinct in Chaucer’s time, for he avoids riming the one with the other; but, in the fifteenth century, the open values began to approximate those of the close. This change gave to open what is practically its modern value, but the other sounds were to undergo further changes in the sixteenth and later centuries. At the same time, medial gh ceased to be pronounced. Chaucer does not rime a vowel followed by ght with a vowel followed by t; but, in Lydgate, “fought” rimes with “about,” and there is ample evidence that the Old English sound of medial h was, by this time, lost.
The orthography during this century was somewhat confused. It was irregular in the sixteenth century, in spite of the influence of printed texts, but already it was assuming forms which, with slight changes, were destined to survive all later modifications of pronunciation, thus producing the anomalies of our modern spelling. After Caxton’s day, old symbols like [char] and p were discarded, and final non-syllabic -e was often used, as in “stone” (nom.), without any etymological warrant: its use, in such cases, being due to analogy with the oblique forms in which it normally occurred.