by Gwindor » Fri Oct 20, 2017 1:21 pm
I have attempted a little more research. My main interest in answering this question is to identify the sanskrit prefix that corresponds to Thai prefix ปฏิ- as in ปฏิบัติ and ปฏิรูป.
I have attempted some searches of online Sanskrit dictionaries/vocabularies, but haven't had any success search for English words like "reform" or "behavior".
However, in keeping with Thainess, I applied the methods of His Majesty King Rama IV, who took pains to learn English by first looking up Thai words in a Pali dictionary, then looking up the Pali in Sanskrit, then looking up the Sanskrit in English. In this case I searched English words in Hindi, knowing that a great deal of Hindi vocabulary is from Sanskrit. In general, I came up with words that didn't help, but I saw a few that began प्रति- . If this were transcribed directly into Thai using standard equivalents from "the grid" it would be spelled ปรติ- which doesn't quite fit. But it may be that Sanskrit ปรติ- is equivalent to Pali ปฏิ- .
This doesn't neatly answer the question about ฏ in the Sanskrit grid, but it seems likely enough that I can move on. In my somewhat Ptolemaic little system for understanding how Thai words relate to Sanskrit, I stay with my answers and let the anomalies accumulate until a more Copernican method is available.