Further vowels are derived by combining the a sound with i and u to form the four compound vowels (sandhyaksara). The e sound arises when a is sounded through the i e /V mouth position. Remember that a has a relaxed throat
and tongue, while i has the back of the tongue raised and
a > i the throat tense: so relaxing the throat while retaining the back of the tongue raised will produce e. The vowel e sounds similar to that in 'fair' or 'eight'. The ai sound arises when e is further combined with a as it were. Now the only difference between e and a is ai J / the raised back of the tongue, so to move from e towards
the a sound, we need to drop the back of the tongue to
a > e a position half way between that used for i and e and the relaxed position used for a. The ai sounds similar to the vowel in 'aisle' or 'pie'; there should be no glide or slide in the sound from a to i. o In a manner similar to the arising of e, when a is sounded / through the u mouth position, i.e. with the lips in the
position for u but the throat relaxed for sounding a, the
sound o naturally arises. The vowel o should sound between 'awe' and 'owe' (or between the vowel sounds in 'corn' and 'cone'); the ideal is that point where the sound could be taken as either of the two English sounds. au And finally, the au sound arises when a is combined / with o, so that the position of the lips is roughly half
way between that used for u and a, and the throat is
relaxed. The au sounds similar to the vowel in 'down' or 'hound' but without the glide from a to u.