32. Vowels are sounds which are produced by the vibrations of the vocal
chords (this may be easily felt by placing a finger on the throat at the
Adam’s apple) and without any audible friction or any obstruction
anywhere in the passage above the vocal chords. The difference in the
sound of the vowels is due to the different shape which the position of
the tongue and the lips gives in each case to the cavity of the mouth.
During the pronunciation of pure vowels no air escapes through the nose.
33. The simple vowels, #a#, #e#, #i#, #o#, #u# (#y#), are either _long_
or _short_. The sound of a long vowel is considered to be twice the
length of that of a short.
34. That a long vowel is equal to two shorts is a rule of metrical
theory (see 2515). In actual pronunciation, there were undoubtedly
various degrees of length, as in English: e.g., _sea_, _seize_ (long),
_cease_ (half-long).