Most of the time people reduce vowels in speech when these are not stressed, but sometimes these unstressed vowels are fully pronounced, too. For example, most people reduce the [ɪ] to schwa and say /bəˈliv/ instead of /bɪˈliv/, but they don't say /əˈkwɪp mənt/ in place of /ɪˈkwɪp mənt/ or /əˈkɒn ə mi/ instead of /ɪˈkɒn ə mi/.

This also happens with other vowels like [i]. For example, the [i] in the word /ˈbɪz i/ is unstressed, yet it keeps its original sound, i.e it's fully pronounced.

Why does this happen? Can we always reduce vowel sounds in words in which they are not stressed? Or when should we reduce them, and when should we not?

  • You haven't taken into account which vowels can be reduced, I personally never reduce the /i/ sound whether it is stressed or not. That would explain all of your examples. Oct 23, 2015 at 1:32
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    So in short: no, you cannot always reduce unstressed vowels. Look in a dictionary: they generally show reduced vowels in their pronunciation guides, and if there's variance between speakers, a good pronunciation dictionary should show that as well.
    – herisson
    Oct 23, 2015 at 1:40
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    @sumelic: also /u/: bayou, kudzu, menu, value, virtue, voodoo. Nov 7, 2015 at 3:04
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    @PeterShor: Good point! I wonder why /u/ is generally not listed (in sources I can find). Maybe it's because there's no word I can think of with /t/ before fully unstressed final /u/ (since it seems t-flapping is considered one of the clearest pieces of evidence differentiating fully unstressed and secondarily stressed syllables).
    – herisson
    Nov 7, 2015 at 4:29
  • @sumelic: doesn't the fact that we have to pronounce the yod in value /ˈvalju/ mean the syllable in unstressed? If it had primary or secondary stress, Americans could drop the yod (e.g., solution or illumination.) Nov 7, 2015 at 16:49

1 Answer 1


Word-final position is special. Full vowel reduction to schwa doesn't occur in general for word-final unstressed vowels, but there are special neutralizations that apply in this context.

The most common word-final unstressed vowels are:

  • "commA". This is typically transcribed as the phoneme /ə/, but in many accents it is realized phonetically as a more open vowel than word-medial /ə/. It may be something like [ɐ], or similar to the quality of /ʌ/.

  • "lettER". This is merged with "commA" as /ə/ in a Southern British English accent. In American English, it is a rhotic vowel or a syllabic r, transcribed as /əɹ/, /ɚ/ or /ɹ̩/.

  • "grottO". In standard British and American English accents, this is just the "goat" vowel (usually transcribed /əʊ/ in British English, and /oʊ/ or /o/ in American English) in an unstressed syllable. In some non-standard dialects, it may be merged with "commA" or "lettER", at least in some words—as a result, the word "potato" has a variant form "tater" that comes from a dialectal pronunciation.

  • "happY". In a standard American English accent, this is identified with the vowel in the word "fleece", and transcribed as /i/. In British English, there is a bit more variability. Old-fashioned "RP" English used the quality [ɪ] for this vowel, and so at a certain point (Jack Windsor Lewis suggests the first clear evidence is sometime around the 19th century) it became common for British phonologists to identify it with the vowel phoneme /ɪ/.

    However, pronunciations with a quality closer to [i] do exist in British English as well as in American English, so recent dictionaries of British English may transcribe it as /i/, using the same vowel symbol as the "fleece" vowel but omitting the length marker. The use of three symbols in transcription should not be understood to mean that there is a three-way phonemic contrast in any form of English between /iː/, /i/ and /ɪ/. It can be analyzed as a neutralization of the contrast between /iː/ and /ɪ/.

    In some non-standard accents, it may be merged with "commA" as /ə/, at least in some words. Notably, the American state Missouri has a variant pronuciation ending in /ə/ ("Missoura").

A somewhat less commonly encountered unstressed word-final vowel can perhaps be found in the last syllable of the word "continue". It is possible to analyze this as a "weak" variant of the vowel /uː/, parallel to how the "happy" vowel can be analyzed as a "weak" variant of /iː/. Windsor Lewis says:

What has become a problem for pronunciation lexicographers is that, having given recognition to the weak /i/ of happy etc, they could hardly refuse to recognise the parallel weak /u/ of thankyou for which / `θæŋkju:/ if fully strong must surely sound unnaturally deliberate delivery or a bit of a regionalism. But so far they've done so very grudgingly:both the Longman Pronunciation Dictionary and the (Jones, Roach et al.) English Pronouncing Dictionary give /-u/ for the name of the letter w only in second position. Yet ˈdouble u and ˈw make a quite feasible minimal pair of sorts. For the noun thank(-)you LPD gives only /-u:/ while EPD gives only /-u/. They both agree on recognising (only as a subvariant) /-u/ as a possibility in continue. Only LPD shows /-u/ as possible for value.

The OED doesn't seem to use the symbol /u/ in its transcriptions.

As far as I know, other unstressed vowel phonemes are fairly rare in word-position, but they can occur (except for the "checked" vowel phonemes /ɛ/, /ɒ/, /æ/) and are not reduced. It's unclear to me to what extent a word-final syllable ending in one of the the following vowels should be analyzed as having secondary (or tertiary) stress.

  • /eɪ/ in essay (which the OED says may have final primary stress in the past), and also for many speakers in Monday etc.--but some speakers have the "happy" vowel in -day.

  • /ɔɪ/ in alloy, which the OED says used to have final primary stress

  • /aɪ/ in various words, including Latin plural forms.

A non-final unstressed vowel that comes before a consonant typically can be reduced to /ə/ in at least some accents

As an American English speaker with the "weak vowel merger" (at least, I'm mostly merged in my perception of these sounds), neither /əˈkwɪp mənt/ nor /əˈkɑn ə mi/ seems impossible to me. I would say that the initial vowel in these words can be fully reduced.

Before a vowel, neither "happY" nor the /u/ sound (which I don't know a good example word for) is reduced to shwa--or at least, it's not standard for careful speech. A word like "valuable" may in fact be reduced to something that sounds like "valyable", but the rules for "compressions" like this are rather complicated so I don't know if I can cover them in this post.

Works cited


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