160. A final sonant aspirate

If, however, a final sonant aspirate of a root is followed by त् t or थ् th of an ending, the assimilation is in the other direction, or progressive: the combination is made sonant, and the aspiration of the final (lost according to 153, above) is transferred to the initial of the ending.

Thus, gh with t or th becomes gdh; dh with the same becomes ddh, as buddhá (√budh + ta), runddhás (√rundh + thas or tas); bh with the same becomes bdh, as labdhá (√labh + ta), labdhvā́ (√labh + tvā).

a. Moreover, h, as representing original gh, is treated in the same manner: thus, dugdhá, dógdhum from duh—and compare rūḍhá and līḍhá from ruh and lih, etc., 222 b.

b. In this combination, as the sonant aspiration is not lost but transferred, the restoration of the initial aspiration (155) does not take place.

c. In dadh from √dhā (155 e), the more normal method is followed; the dh is made surd, and the initial aspirated: thus, dhatthas, dhattas. And RV. has dhaktam instead of dagdham from √dagh; and TA. has inttām instead of inddhām from √idh.