In English, many vowel shifts affect only vowels followed by in rhotic dialects, or vowels that were historically followed by that has been elided in non-rhotic dialects. Most of them involve the merging of vowel distinctions and so fewer vowel phonemes occur before than in other positions of a word.
Overview
In rhotic dialects, is pronounced in most cases. In General American English (GA), is pronounced as an approximant or in most positions, but after some vowels, it is pronounced as r-coloring. In Scottish English, is traditionally pronounced as a flap or trill , and there are no r-colored vowels.
In non-rhotic dialects like Received Pronunciation (RP), historic is elided at the end of a syllable, and if the preceding vowel is stressed, it undergoes compensatory lengthening or breaking (diphthongization). Thus, words that historically had often have long vowels or centering diphthongs ending in a schwa , or a diphthong followed by a schwa. earth: GA , RP here: GA , RP fire: GA , RP
In most English dialects, there are vowel shifts that affect only vowels before or vowels that were historically followed by . Vowel shifts before historical fall into two categories: mergers and splits. Mergers are more common and so most English dialects have fewer vowel distinctions before historical than in other positions of a word.
In many North American dialects, there are ten or eleven stressed monophthongs; only five or six vowel (rarely seven) contrasts are possible before a preconsonantal and word-final (beer, bear, burr, bar, bore, bor, boor). Often, more contrasts exist if appears between vowels of different syllables. In some American dialects and in most native English dialects outside North America, for example, mirror and nearer do not rhyme, and some or all of marry, merry, and Mary are pronounced distinctly. (In North America, those distinctions are most likely to occur in New York City, Philadelphia, some of Eastern New England (including Boston), and in conservative Southern accents.) In many dialects, however, the number of contrasts in that position tends to be reduced, and the tendency seems to be towards further reduction. The difference in how the reductions have been manifested represents one of the greatest sources of cross-dialect variation.
Non-rhotic accents in many cases show mergers in the same positions as rhotic accents even though there is often no phoneme present. That results partly from mergers that occurred before the was lost and partly from later mergers of the centering diphthongs and long vowels that resulted from the loss of .
The phenomenon that occurs in many dialects of the United States is one of tense–lax neutralization in which the normal English distinction between tense and lax vowels is eliminated.
In some cases, the quality of a vowel before is different from the quality of the vowel elsewhere. For example, in some dialects of American English, the quality of the vowel in more typically does not occur except before , and it is somewhere in between the vowels of maw and mow. It is similar to the vowel of the latter word but without the glide.
It is important to note, however, that different mergers occur in different dialects. Among United States accents, the Boston, Eastern New England and New York accents have the lowest degree of pre-rhotic merging. Some have observed that rhotic North American accents are more likely to have such merging than non-rhotic accents, but that cannot be said of rhotic British accents like Scottish English, which is firmly rhotic but has many varieties with the same vowel contrasts before as before any other consonant.
Mergers before intervocalic R
Most North American English dialects merge the lax vowels with the tense vowels before and so "marry" and "merry" have the same vowel as "mare," "mirror" has the same vowel as "mere," "forest" has the same vowel as the stressed form of "for," and "hurry" has the same vowel as "stir" as well as that found in the second syllable of "letter". The mergers are typically resisted by non-rhotic North Americans and are largely absent in areas of the United States that are historically largely nonrhotic.
Hurry–furry merger
The hurry–furry merger occurs when the vowel before intervocalic is merged with . That is particularly a feature in many dialects of North American English but not New York City English, Mid-Atlantic American English, older Southern American English, some speakers of Eastern New England English, and speakers of Southeastern New England English. Speakers with the merger pronounce hurry to rhyme with furry and turret to rhyme with stir it.
