Classifying the Vowels Sounds of English.

- http://www.indiana.edu/~gasser/L503/vowels.gif Classifying the Vowels Sounds of English
The classifcation of vowels is based on four major aspects: Tongue height - according to the vertical position of the tongue (high vowels, also referred to as close; low vowels, also referred to as open; intermediate - close-mid and open-mid) Frontness vs. backness of the tongue - according to the horizontal position of the highest part of the tongue. Lip rounding - whether the lips are rounded (O-shape) or spread (no rounding) when the sound is being made. Tenseness of the articulators - refers to the amount of muscular tension around the mouth when creating vowel sounds. Tense and lax are used to describe muscular tension. | Front vowels(tongue body is pushed forward) | Central vowels(tongue body is neutral) | Back vowels(tongue body is pulled back) | High/close vowels(tongue body is raised) | /http://www.studyenglishtoday.net/Phon_symb/pi.gif/ see/http://www.studyenglishtoday.net/Phon_symb/iletter.gif/ sit | | /http://www.studyenglishtoday.net/Phon_symb/pu.gif/ boot/http://www.studyenglishtoday.net/Phon_symb/upsilon.gif/ book | Mid vowels(tongue body is intermediate) | /e/ bait*/http://www.studyenglishtoday.net/Phon_symb/epsilon.gif/ bet | /http://www.studyenglishtoday.net/Phon_symb/schwa.gif/ sofa**, /http://www.studyenglishtoday.net/Phon_symb/pe.gif/ bird | /o/ boat*/http://www.studyenglishtoday.net/Phon_symb/po.gif/ bought*** | Low/open vowels(tongue body is lowered) | /http://www.studyenglishtoday.net/Phon_symb/pshorta.gif/ bat | /http://www.studyenglishtoday.net/Phon_symb/caret.gif/ under** | /http://www.studyenglishtoday.net/Phon_symb/pa.gif/ father, /http://www.studyenglishtoday.net/Phon_symb/pho.gif/ sock(BrE) |

*In some American accents (especially Californian English), vowel sounds in words such as bait, gate, pane and boat, coat, note are not consider diphthongs. American phonologists often class them as tense monophthongs (/e/ and /o/).**/http://www.studyenglishtoday.net/Phon_symb/schwa.gif/ is used in unstressed syllables, while /http://www.studyenglishtoday.net/Phon_symb/caret.gif/ is in stressed syllables. The vowel /http://www.studyenglishtoday.net/Phon_symb/caret.gif/ used to be a back vowel, and the symbol was chosen for this reason. This is no longer a back vowel, but a central one.***A considerable amount of Americans don't have the deep /http://www.studyenglishtoday.net/Phon_symb/po.gif/ in their vocabulary, they pronouce bought, ball, law with the deep /http://www.studyenglishtoday.net/Phon_symb/pa.gif/ sound.
According to the position of the lips: English front and central vowels are always unrounded. English back vowels /http://www.studyenglishtoday.net/Phon_symb/pu.gif/, /http://www.studyenglishtoday.net/Phon_symb/upsilon.gif, /o/, /http://www.studyenglishtoday.net/Phon_symb/po.gif/ are rounded (/http://www.studyenglishtoday.net/Phon_symb/pa.gif/ vowel is unrounded).
Vowel Tenseness: Tense vowels (produced with a great amount of muscular tension): /http://www.studyenglishtoday.net/Phon_symb/pi.gif/, /http://www.studyenglishtoday.net/Phon_symb/po.gif/, /http://www.studyenglishtoday.net/Phon_symb/pu.gif/, /http://www.studyenglishtoday.net/Phon_symb/pe.gif/, /http://www.studyenglishtoday.net/Phon_symb/pa.gif/. Tense vowels are variable in length, and often longer than lax vowels. Lax vowels (produced with very little muscular tension): /http://www.studyenglishtoday.net/Phon_symb/iletter.gif/, /http://www.studyenglishtoday.net/Phon_symb/epsilon.gif/, /http://www.studyenglishtoday.net/Phon_symb/pshorta.gif/, /http://www.studyenglishtoday.net/Phon_symb/upsilon.gif/, /http://www.studyenglishtoday.net/Phon_symb/pho.gif/, /http://www.studyenglishtoday.net/Phon_symb/caret.gif/, /http://www.studyenglishtoday.net/Phon_symb/schwa.gif/. Lax vowels are always short.