Stress and Vowel Reduction in English - Unstressed Full Vowels

Unstressed Full Vowels

All full (unreduced) vowels may occur in unstressed position (except under the approaches that routinely assign secondary or tertiary stress to syllables containing such vowels – see Degrees of lexical stress below). Some examples of words with unstressed syllables that are often pronounced with full vowels in Received Pronunciation are given below (pronunciation may be different in other varieties of English).

• Unreduced short vowels: /ɛ/ in the final syllable of document when used as a verb (compare the /ə/ heard when the word is used as a noun); /æ/ in the first syllable of ambition; /ɒ/ in the second syllable of neon; /ʌ/ in words with the negative prefix un-, such as unknown (compare /ə/ in until).
• Long vowels: /ɑː/ in the final syllable of grandma; /ɔː/ in the final syllable of outlaw; /uː/ in tofu; /ɜː/ in the noun convert; /iː/ in manatee. Note that this last may stand in contrast to the happY vowel found at the end of humanity. This contrast is further described under Distinctions between reduced and unreduced vowels below.
• Diphthongs: /eɪ/ in Monday; /əʊ/ in piano; /aʊ/ in discount; /aɪ/ in idea; /ɔɪ/ in royale.

Full vowels can often be found in unstressed syllables in compound words, as in bedsheet, moonlit, tentpeg, snowman, and kettledrum. However in some well-established compounds the vowel of the unstressed part may be reduced, as in postman /ˈpəʊstmən/.

Many other full unstressed vowels also derive historically from stressed vowels, due to shifts of stress over time (such as stress shifting away from the final syllable of French loan words, like ballet and bureau, in British English), or the loss or change of stress in compound words or phrases (as in óverseas vóyage from overséas or óverséas plus vóyage). There is a tendency, though, for such vowels to become reduced over time, especially in common words.

With vowels represented as /ɪ/ and /ʊ/, it may be hard to ascertain whether they represent a full vowel or a reduced vowel. An example of a word which may be considered to illustrate the contrast is chauvinism, where the first i may be regarded as an instance of the reduced vowel, and the second as unreduced /ɪ/.