Phonological history of English open back vowels

Overview

Old and Middle English

• , spelt, as in dog, god
• , often spelt, or before consonant+vowel or certain consonant pairs, as in boat, whole, ''old''

16th-century changes

• The long vowel of boat had been raised to as a result of the Great Vowel Shift.
• The diphthong found in words such as cause, law, all, salt, psalm, half, change, chamber, dance had become an open back monophthong or.
• At this time, the short in dog was lowered to

• as in lot
• or as in cause

• as in ''low''

17th-century changes

• The diphthong of soul was raised to, and then monophthongized to, merging with boat. Before, this vowel further merged with due to the horse–hoarse merger except in some varieties, as currently seen in Irish English, Scottish English and African American Vernacular English.
• Short was retracted and rounded to. The shift was suppressed before a velar consonant, as in quack, twang, wag, wax, and also was suppressed by analogy in swam. The change of to did not occur in Mid-Ulster English.
• had begun to partake in lengthening and raising before a nonprevocalic voiceless fricative or /r/. That resulted in words like broth, cost and off having instead of, and was the start of the split.
• In words such as change and chamber, the pronunciation was gradually replaced in the standard language by a variant with, derived from Middle English. That explains the contemporary pronunciation of these words with.
• However, when preceded, as in laugh and half, was shifted to instead, derived from Middle English.
• An unrounded back vowel developed, found in certain classes of words that had previously had, like start, father and palm.

• in lot and want.
• in cloth and cost.
• in start, father and palm.
• in tor, cause, and corn.

Later changes

• The three-way distinction between,, and was simplified in one of two ways:
• * In General American and old-fashioned RP, was raised to, merging with the vowel in .
• * In many accents of England, the lengthening of the set was undone, restoring the short pronunciation. This became standard RP by the mid-20th century.
• In General American, the lot vowel has become unrounded and merged into .

• in lot, want, cloth, and cost.
• in tor, cause, and corn.
• in start, father, and palm.

• in lot, want, start, father, and palm.
• in tor, cause, corn, cloth and cost.

Variation in present-day English

Unrounded

• Most of Irish English
• Much of the Caribbean
• Norwich
• The West Country and the West Midlands of England
• Most of North American English
• * Excluding northeastern New England English and Western Pennsylvania English, where it is typically raised toward, merging with the vowel in thought.

''Father–bother'' merger

split

''Cot–caught'' merger

merger

split

Distribution of

• In non-rhotic dialects spoken outside of North America, corresponds mostly to in General American and so is most often spelled. In dialects with the trap–bath split, it also corresponds to GA, which means that it can also be spelled before voiceless fricatives. In those dialects, and are separate phonemes.
• In native words, in most non-rhotic speech of North America corresponds to both in GA and in RP, as those dialects feature the father–bother merger.
• North American English features the father–bother merger, where often corresponds to in RP. Only New York City English and New England English distinguish between the two, and with an unrounded vowel. Modern-day New York City English also has rounded for reflexes of, which ironically, came from an unrounded vowel.
• The cot–caught merger usually occurs in addition to the father–bother merger. This applies to almost all of Canadian English and many varieties of American English. The result is usually, the vowel, which is used for as well. Some dialects will have as the merged vowel, not ; these include Standard Canadian English or Pittsburgh English.
• * The caught-cot merger without the father–bother merger is found in Scottish English and most of New England English.
• In loanwords and names, the open central unrounded vowel in a source language is regularly approximated with in North America and in RP. However, in the case of mid back rounded vowels spelled, the usual North American approximation is, not . However, when the vowel is both stressed and word-final, the only possibilities in RP are in the first case and in the latter case, mirroring GA.

Fronted