English vowels

English vowels are best described as phonemes, or distinctive sounds, of the major varieties of English (e.g., North American, British, Australian), along with various phonetic differences in the various dialects. The number of phonemes varies, depending on these major varieties -- North American English (NAE), British English (BE) or Recieved Pronunciation (RP), and Australian English (AE).

Phonemes are distinguished by minimal pairs, which demonstrate that sounds are distinctive and meaningful units in the language. For example, pairs like these show that these two vowels are distinctive and unique sounds of English, and not variants of one another.

• bit /bɪt/ vs. beat /bit/
• bet /bεt/ vs. bait /bεɪt/
• bought /bɔt/ vs. boat /bɔʊt/

1 Short and long vowels

The short vowels are lax, or produced with a relaxed tongue muscle, which include the phonetically simple vowels, or monophthongs, which consist of a single phonetic segment. These can occur in stressed or unstressed syllables. The long vowels of English occur in stressed syllables (either a primary or a secondary word stress), and are diphthongs, or double vowels, consisting of two phonetic elements. These can be glide diphthongs, where the core element glides into a nearby vowel element, or full full diphthongs like /ai/, which involve a transition to a different vowel in the oral space. In unstressed syllables we often have reduced vowels that are extra-short vowels that central vowels (produced in the center of the oral space, such as the schwa /ə/) or centralized, namely, a variety of /ɪ/ that is realized further back toward the center than the usual /ɪ/. The standard vowels of North American English are shown below, along with common British analogues.

Full monophthongs	Glide diphthongs	Full diphthongs	Reduced vowels
BIT ɪ BET ε (US) e (UK) BATH æ (NAE) a (UK) TRAP æ PALM ɑ: LOT ɑ (NAE) ɔ, ɒ (UK) CLOTH ɑ (NAE) ɔ, ɑ (UK) BOUGHT o, ɔ (US) ɔ: (UK) STRUT ə (ʌ) PURSE ɜ (UK) FOOT ʊ	FACE eɪ BOAT ɔʊ (US) əʊ (UK) BEAT iː (ij) FOOD u: (uw)	BITE aɪ CHOICE ɔɪ MOUTH aʊ	COMMA ə LETTER əɹ (ɚ) (US) ɜ (UK)

The following are allophones, or variants, of vowels in reduced or unstressed syllables.

HAPPY	ɪ (UK)
MESSAGE	ɪ̈ (ɨ)

2 North American English

These are the general vowel phonemes of North American English. Since tense vowels are long, the length symbols as in /i:/ can be used, but since tenseness necessarily implies that they are long in English, these symbols are not entirely necessary, and are omitted here.

General American

	Front		Central	Back
	lax	tense	lax	lax	tense
Close	ɪ	i		ʊ	u
Mid	ɛ	eɪ	ə (ʌ)	ɔ	ɔʊ
Open	æ				ɑ
Diphthongs	aɪ   ɔɪ   aʊ

General American with examples

	Front				Central		Back
	lax		tense		lax		lax		tense
Close	ɪ	BIT	i (i:)	BEAT			ʊ	BOOK		u BOOT
Mid	ɛ	BET	eɪ	BAIT	ə (ʌ)	BUT	ɔ	BOUGHT	ɔʊ (ou)	BOAT
Open	æ	BAT					ɑ	BODY

Diphthongs
aɪ	BITE
ɔɪ	BOY
aʊ	BOUT

The following are so-called rhotic vowels, or a vowel plus an <r> sound. Since the English <r> or /ɹ/ is a semi-consonantal glide, some phoneticians might consider such combinations to be diphthongs or triphthongs.

Rhotic vowels (V+r)

	Front		Central		Back
Close	BEER	ɪr (UK), ir (US)			TOUR	ʊr
Mid	BEAR	ɛr	BURR	ʌr (ər)	BOAR	ɔr
Open	BAR	ar

3 British: Received Pronunciation

These are the general vowel phonemes of standard British or received pronunciation.

Received Pronunciation

	Front		Central		Back
	short	long	short	long	short	long	glided
Close	ɪ	i:			ʊ	u:
Mid	ɛ	eɪ	ə (ʌ)	ɜː	ɔ	ɔː	ɔʊ
Open	æ		a		ɒ	ɑː
Diphthongs	eɪ   aɪ, ɔɪ   aʊ   əʊ ɪə   ʊə
Triphthongs	(eɪə   aɪə   ɔɪə   aʊə   əʊə)

4 Australian

These are the general vowel phonemes of General Australian English.

General Australian

	Front		Central		Back
	short	long	short	long	short	long
Close	ɪ	iː		ʉː	ʊ	oː
Mid	e	eː	ə	ɜː	ɔ
Open	æ		ɐ	ɐː
Diphthongs	æɪ   ɑɪ   oɪ   æɔ   əʉ ɪə   (ʊə)

5 References

1. Most tables here were adapted from the Wikipedia article on English phonemes, due to time limitations.