|IPA symbol||Examples||IPA symbol||Examples|
|/i/||beat, see||/u/||boot, shoe|
|/ɪ/||bit, him||/ʊ/||book, pull|
|/eɪ/||bait, face, they||/oʊ/ or /ow/||home, blow, boat|
|/ɛ/||bet, leg, head||/ɔ/||caught, naught|
|/æ/||black, mat, apple||/ɑ/||cot, not|
|/ʌ/||but, mother||/aɪ/||eye, bite, sight|
|/ə/||sofa, until, combine||/aʊ/ or /aw/||cloud, shroud, cow|
|/ɔɪ/ or /oy/||boy, choice, noise|
It can be argued that, while consonants can provide difficulties, it is the vowels that can be the most damaging to a person’s intelligibility. It is important to note, however, that there are a few English monophthong (single vowel) distinctions which should not be a major concern, namely /ɑ/-/ɔ/-/ɒ/. While some North American and British dialects still distinguish the /ɑ/ in “cot” from /ɔ/ in “caught,” other North American and British dialects use only one low-back vowel whose phonetic quality can vary widely, with some regions and individuals pronouncing it more like /ɑ/and some more like /ɔ/.
- /ɑ/ in “cot”
- /ɔ/ in “caught”
Besides monophthongs, all L1 English dialects also include diphthongs (two adjacent vowels within a single syllable that are processed by listeners as a single vowel). However, only a few of these diphthongs are present across dialects, namely /aɪ/ in words like “tide,” /aʊ/ in words like “doubt” and /ɔɪ/ in words like “toy.” Therefore L2 English speakers must acquire only these phonemic diphthongs to avoid compromised intelligibility.
- /aɪ/ in words like “tide”
- /aʊ/ in words like “doubt”
- /ɔɪ/ in words like “toy”
Additional English diphthongs mark regional accent but are not phonemic, that is, reduced intelligibility is not likely to result if speakers use the pure vowel /o/ instead of the diphthong /oʊ/ when pronouncing words such as “toe” or the pure vowel /e/ instead of the diphthong /eɪ/ when pronouncing words like “day” (or vice versa). However, L2 speakers of English, particularly if their L1 includes only monophthongs, a.k.a. pure vowels (e.g., Spanish), frequently struggle to glide from the initial to final vowel of even the phonemic diphthongs of English.