128. As regards the accent of these vowel combinations, it is to be noticed that, 1. as a matter of course, the union of acute with acute yields acute, and that of grave with grave yields grave; that of circumflex with circumflex cannot occur; 2. a circumflex with following acute yields acute, the final grave element of the former being raised to acute pitch; a grave with following acute does the same, as no upward slide of the voice on a syllable is acknowledged in the language; but, 3. when the former of the fused elements is acute and the latter grave, we might expect the resulting syllable to be in general circumflex, to represent both the original tones. Pāṇini in fact allows this accent in every such case; and in a single accented Brāhmaṇa text (ÇB.), the circumflex is regularly written. But the language shows, on the whole, an indisposition to allow the circumflex to rest on either long vowel or diphthong as its sole basis, and the acute element is suffered to raise the other to its own level of pitch, making the whole syllable acute. The only exception to this, in most of the texts, is the combination of í and i, which becomes ī̀: thus, divī̀ ’va, from diví iva; in the Tāittirīya texts alone such a case follows the general rule, while ú and u, instead, make ū̀: thus, sū̀dgātā from sú-udgātā.
129. The i-vowels, the u-vowels, and ऋ ṛ, before a dissimilar vowel or diphthong, are regularly converted each into its own corresponding semivowel, य् y or व् v or र् r. Examples are:
इत्याह ity āha (iti + āha);
मध्विव madhv iva (madhu + iva);
दुहित्रर्थे duhitrarthe (duhitṛ-arthe);
स्त्र्यस्य stry asya (strī + asya);
वध्वै vadhvāi (vadhū-āi).
a. But in internal combination the i and u-vowels are not seldom changed instead to iy and uv—and this especially in monosyllables, or after two constants, where otherwise a group of consonants difficult of pronunciation would be the result. The cases will be noticed below, in explaining inflected forms.
b. A radical i-vowel is converted into y even before i in perfect tense-inflection, so ninyima (ninī + ima).
c. In a few sporadic cases, i and u become iy and uv even in word-composition: e.g., triyavi (tri + avi), viyan̄ga (vi + an̄ga), suvita (su + ita): compare 1204 b, c.
d. Not very seldom, the same word (especially as found in different texts of the older language) has more than one form, showing various treat-