Reduced vowels

In unstressed syllables, English permits a narrower range of vowels than in stressed syllables; and there are a number of vowels which are particular to unstressed syllables, often known as reduced vowels. The main ones are the unstressed vowels of HAPPY, COMMA and WANTED.

The HAPPY vowel is usually a close front vowel such as [i] or [I]. In some varieties it may be much more open, as in north west England or some parts of the Southern USA, where it can be close to [e] or [ε].

The comma vowel is canonically a mid central vowel in the region of [ə] (though see notes on individual varieties above), but it is particularly susceptible to its surrounding context. For example, in the phrases ‘to the  park’ vs ‘to the  hill’, there are backer vs. fronter qualities respectively, reflecting the vowels of the words ‘park’ and ‘hill’. This is a form of ‘vowel harmony’, where the vowels in a stretch of speech share some phonetic property (here, frontness or backness).

The vowel of WANTED varies along the front–back dimension, with some varieties having [I], others having backer vowels such as  , or indeed the same vowel as COMMA.

Many function words (prepositions, auxiliary verbs, pronouns and determiners) in English have ‘strong’ and ‘weak’ forms, where the ‘strong’ form contains a ‘full’ vowel and the ‘weak’ form (which is always unstressed) contains a ‘reduced’ vowel. Weak forms are generally pronounced without [h]. Compare the vowels in the underlined words in the following sentences (stress is marked  ):