Ahom Letter Dda

It writes Pali’s “ḍ”: a D with the tongue tip curled back.

The oldest surviving Ahom text is the Snake Pillar inscription, made during King Siuw Hum Miung’s reign (1497–1539). Ahom writing also appears on stones, coins, brass plates, and manuscripts. Although use of Tai Ahom declined from the late 17th century, priests retained the language and script for religious practice through the 19th century. A 1920 dictionary marks the beginning of modern script use; a 1997 computer font helped Ahom texts reach print faster. Those milestones belong to Ahom writing generally, not this letter.

𑝃 belongs to a later Pali extension. The World Tipiṭaka in Tai Scripts: 15-Script Set is a collection of Buddhist scriptures in Pali created for the Ahom script. As of 2020, it was the only known publication using these added letters.

Is 𑝃 part of ordinary Ahom spelling?

No; it belongs to the Pali extension.

Ordinary Ahom uses 𑜓 for D pronounced near the teeth. The Pali extension formed 𑝃 by adding a dot to that letter, marking a tongue-curled D. 𑝄 represents the same tongue-curled sound with a puff of breath.