II Vowels
It often happens that two sounds, though formed in different ways,
have nearly the same effect on the ear. Thus the English vowel in
'turn' is formed in a totally different way from the French one in
'peur', the former being an unrounded, the latter a rounded vowel
and yet they are hardly distinguishable by an untrained ear. The
consequence is that two such vowels are never employed together
in the same language to distinguish the meanings of words and
for practical purposes they may be considered as variations of the
same vowel. Hence we have to distinguish not so much between
sounds as between groups of sounds. One of the most important
distinctions of these groups is that of 'close' and 'open', the open
vowels being generally formed by a 'low' position of the tongue
or by some other widening of the mouth passage.
Disregarding special exceptions in individual languages, we may
assume the following as the chief distinctive groups in language
generally:
(1) the dull-back,
(2) the clear-back,
(3) the mixeda,
(4) the high-front,
(5) the close-front,
(6) the open-front,ROUNdEd.
(7) high-back,
(8) close-back,
(9) open-back,
(10) high-front,but.
father.
tum, father, gabe (German).
bit, beat.
etC (French).
men, mare, man.full, fool.
so (German).
folly, fall.
lune (French).