Phonology: case studies

Vowel reduction in English

General American English, or GAE, has a vowel inventory similar in many respects to that of Catalan. Like Catalan, GAE has the vowel phonemes /i e ɛ a ɔ o u/. In addition to these, GAE also has the high vowel phonemes /ɪ ʊ/, which Catalan does not have.

(3) Features for the vowel phonemes of General American English.

	i	ɪ	e	ɛ	o	ɔ	u	ʊ	a
[high]	+	+	-	-	-	-	+	+	-
[back]	-	-	-	-	+	+	+	+	+
[round]	-	-	-	-	+	+	+	+	-
[ATR]	+	+	-	-	+	-	+	-	-
[low]	-	-	-	-	-	-	-	-	+

GAE also has the vowel schwa, which is not contrastive, but is rather a phonetic variant of a subset of the contrastive vowels in (3). The pairs of related words in (4) show that the mid and low vowel phonemes /e ɛ a ɔ o/ of GAE have schwa as a surface allophone. In each related word pair, corresponding vowels have been highlighted using bold type (for example, the vowel spelled 'a' in primate and primatology). The fact of interest is that taken as a group, these pairs show that each of the vowels [e ɛ a ɔ o], seen in the first member of the pair, alternates with [ə] in the second member of each pair.

(4) Vowel reduction in English.

Alternating sounds		Examples
		Phonetic symbols		Orthography
Low Vs	[æ] ~ [ə]	[ǽ.ɾəm]	[ə.tʰá.mɪk]	atom / atomic
	[a] ~ [ə]	[ə.tʰá.mɪk]	[ǽ.ɾəm]	atomic / atom
Mid Vs	[e] ~ [ə]	[pʰráj.mèt]	[pʰràj.mə.tá.lə.ʤi]	primate / primatology
	[ɛ] ~ [ə]	[dɛ̀.mə.lɪ́.ʃən]	[də.má.lɪʃ]	demolition / demolish
	[o] ~ [ə]	[fó.tò]	[fó.ɾə.gɹæ̀f]	photo / photograph
	[ɔ] ~ [ə]	[pɔ̀.ɹɔ́.sɪ.ɾi]	[pɔ́.ɹəs]	porosity / porous (suffix -ous)

The factor determining the alternation we see in (4) is stress: notice that in every case where a non-schwa vowel surface, it occurs in a syllable with primary or secondary stress. Schwa occurs only in unstressed syllables. This alternation occurs only with mid and low vowels. As we see from pairs like civil/civilian and impute/imputation, high vowels do not surface as schwa in unstressed syllables.

There are some things we should bear in mind about English vowels, since this is one of the areas in which English dialects differ richly. First, a standard feature of southern dialects of American English is that the back vowels /u/ and /o/ are centralized, so that they are pronounced [ɵ ʉ]. Some other North American English dialects also do this, to a lesser degree. Second, the vowel we transcribed as [ɔ] in the chart above is quite different from dialect to dialect. One of the authors of this section has the vowel [a] for stressed /ɔ/, and the other has [ɒ]. There are many more things we could say about English vowels - but we won't go any further here! For a more detailed discussion of vowels in American English, see Ladefoged 2001.

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