Weak Vowel Sounds

Weak vowel sounds are found in unstressed syllables in English pronunciation. In standard pronunciation there are 4 weak vowel sounds (in order of frequency) /ə,ɪ,i,u/:

Weak Vowel Sound Spellings

Common spellings for each weak vowel sound in content words are underlined below:

/ə/ annoy, tighter, council, obstruct, submit
/ɪ/ insure, repeat, cottage
/i/ sunny

Weak Sounds in Function Words

In connected speech, function words (prepositions, articles, auxiliaries etc) are normally pronounced as a weak form with one of the weak vowels. If these words are stressed, most will be pronounced with a different vowel sound.

Examples of function words that are pronounced with each weak vowel:

/ə/ are, can, from, but
/ɪ/  him, it, been
/i/ we, he, any
/u/ you, who

Weak Vowels in Connected Speech

THE is pronounced /ə/ before a consonant sound, and /i/ before a vowel sound:

the drill /ðə/
the exercise /ði/

TO is pronounced /tə/ before a consonant sound, and /tu/ before a vowel sound:

to love /tə/
to enjoy /tu/