Students understanding the complexity of language

Chapter 11.9: Vowel Changes


chapter 11.9: vowel sound changes

Vowels are fundamentally different from consonants in several ways that affect how they can change. First, all vowels are voiced, so there cannot be a change in voicing. Second, all vowels are said in the same manner, so there cannot be changes in manner either. Finally, vowels are not produced by placing the tongue in contact with discrete speech organs, so there can be no movement from one part to another either. The features of vowels that can change are frontness, height, roundedness, and tenseness. The causes of these changes can be neighboring consonants, although that is rare. More often, the change is a “long-distance” change in that it is produced by assimilating with vowels in a preceding or following syllable (since vowels form the nucleus of a syllable, other vowels are most often in other syllables). This type of change, where one vowel is influenced by another, is called metaphony.

One type of metaphony vowels undergo is called mutation, where a vowel in one syllable “anticipates” a vowel in a following syllable and changes to become more like it. The structure of a two-syllable word can be written like this CV1CV2C, where C = Consonant and V = Vowel. In mutation V1 changes to become more like V2, because it is easier for the tongue to anticipate the shape it will need to be in for the following vowel. For example, we have a word in which V1 is a low vowel and V2 is a high vowel, V1 could be “raised” to a high vowel to anticipate the height of V2 in the following syllable.

Perhaps the most common example of mutation in English occurred just before the Old English period, when V2 was an [i], a high front vowel. This caused the V1 vowels to mutate towards the front of the mouth. We call this change either front mutation, or i-mutation, or in German, Umlaut, and it has had major effects throughout English. Compare the list of words with back vowels in the first column, followed by related words with fronted vowels in the second:

blood bleed
food feed
mouse mice
man men
drank drench
strong strength
full fill

In all these examples the words on the left hand are the original words and contain back vowels. In the period just before Old English, new words were made out of them by adding suffixes with the high front vowel [i], and this pulled the back vowel in the original word to the front.

Vowels can also be raised or lowered (depending on tongue height). For example, Standard American, the pronunciation of pen is [pɛn] but in the South it is often [pɪn], so that it sounds more like the word pin. The mid front lax vowel /ɛ/ has been raised to the high front lax vowel /ɪ/ because of the following nasal.

Chain shifts

Vowels can also move in what are called chain shifts. This is not a form of assimilation or metaphony. Rather, it is a process of movement that starts with the raising or lowering of one vowel, which results in a chain of all other vowels moving to fill in the resulting gaps. The most famous one in English is the Great Vowel Shift of the 15th through the 18th centuries, but other chain shifts are currently going on in regional dialects of American English. If you are interested, you might look at the charts and descriptions (with audio examples) of the Northern California vowel shift that is currently underway. The Northern Cities Shift explains why vowels of speakers from places like Chicago or Detroit sound so distinctive. We will not be covering these shifts in much detail in this class, mostly because they are still evolving, and therefore are not part of the past history of English.


Reduction is a change in the tenseness of vowel sounds, resulting in less tenseness. Vowels that are reduced change in a progression from tense to lax to schwa to zero or null, i.e., they are lost entirely. This is the standard progression in all English vowels in unaccented syllables, although not all vowels have or will undergo each stage of this progression, and it has had more of an impact on English grammar than anything other sound change.

An example of reduction is the vowel in the word “man,” [mæn], a low, front vowel. When the word stands alone and is stressed, the vowel remains in position. When the word is joined in a compound, as in “chairman,” it is no longer stressed and therefore is reduced. It may be pronounced as a schwa (i.e., moved from the front to the central, that is, neutral, position) [čɛrmən], or even reduced to zero: [čɛrmn̩].

When reduction of a vowel is complete (i.e., the vowel is lost completely), then it is called elision: the loss of a sound because it is unstressed (elision can be used of both consonants and vowels). Elision is widespread in two of our major grammatical categories: the s-plural and the ed-past tense. The plural ending used to be a full syllable, as it remains in some words (“dishes”), but in most words the -e- has reduced to zero, that is, it has been elided. The same reduction has happened in the past tense -ed, which usually takes the form of either a [t] or a [d] on the ends of verbs.

There are specific words to describe different types of elision, depending on where in the word the sound has been lost:

  • apheresis: loss of an unstressed vowel at the front of words: ’bout (for about), ’round (for around)
  • syncope: loss of vowel sounds in the middle of a word: laboratory, comfortable [kəɱftərbəl] (which includes metathesis of the [r] and [t]), family, contractions such as “can’t” or “isn’t” for “cannot” and “is not”
  • apocope: loss of vowels from the end of a word (this has happened historically in many English words; we will see examples later).

Note: these terms, apheresis, syncope and apocope, can refer to loss of both vowels and consonants. Thus, “chile” as a pronunciation of “child” with simplification of the final consonant cluster is an example of apocope, or “fith” as a pronunciation of “fifth” is an example of syncope, as is “won’t” for “will not.” The pronunciations ‘im or ‘e as a pronunciation of “him” or “he” are examples of consonant apheresis. But the most common losses are with unstressed vowels.

Epenthesis: In addition to the loss of sounds, sometimes sounds are added. Epenthesis can be the addition of vowels, such as when “athlete” is pronounced like “athalete,” or of consonants, such as in the following examples: “drownded” for “drowned,” “fambly” for “family” (compare also “chimbly” for chimney” with dissimulation and epenthesis), “hampton” for what was originally “hamton,” “thunder” for what used to be “thunor,” and “sherbert” for “sherbet.”