瑜伽論記 1.524

1.524

十四音者，謂哀阿噎伊鄔烏紇侶紇閭呂盧翳愛汚奧闇惡，不取後二故成十四，迦佉等五，車等五，吒搋等五，多他等五，波披等五，夜邏羅縛賒沙婆訶叉，不取叉字故三十三。

The fourteen vowels are: a, ā, i, ī, u, ū, ṛ, ṝ, ḷ, ḹ, e, ai, o, au, aṃ, aḥ. Not taking the latter two, they constitute fourteen. The five of ka, kha, etc.; the five of ca, etc.; the five of ṭa, ṭha, etc.; the five of ta, tha, etc.; the five of pa, pha, etc.; ya, ra, la, va, śa, ṣa, sa, ha, kṣa. Not taking the letter kṣa, they are thirty-three.