Vowels and tongue position

• Vowels are described in terms of their backness (front/back), tongue height (close, half-close, half-open, open) and lip-rounding (unrounded/rounded).

• The 16 cardinal vowels provide a set of reference points for the location of vowels in the vocal tract.

• These vowels are located on the periphery of the vowel quadrilateral, an idealized model of the vocal tract used by phoneticians for expository purposes.

Vowels 5–8 are back vowels, for which the tongue is raised at the back of the vocal tract. Cardinal 5, , corresponds to the conservative pronunciation of the vowel in the French word pas, and is very close to that of cart in RP. Again, the lips are not rounded, so this is an unrounded open back vowel. Cardinals 6–8, however, are all rounded. Cardinal 6,  , is a half-open vowel, produced at the same tongue height as [ε]. This is the vowel in French sotte; RP has a longer version of this sound in caught [ɔː] (note that the diacritic [ː] is used to indicate vowel lengthening; [ˑ] is used for half-lengthened vowels). Cardinal 7, [o], is the vowel in French beau or Scots English (but not RP) home, while Cardinal 8, [u], brings us back to the same tongue height as for [i], but with the tongue raised at the back of the vocal tract and with lips rounded. This is the vowel of French vous; some conservative RP speakers have a vowel close to this in goose, but most English varieties use a more fronted vowel. (The RP vowel in cat has also changed: the prescribed pronunciation was once [æ], between Cardinals 3 and 4, but the vowel has lowered for almost all RP users since the 1960s).