On the two lists of 'four [types of] words' (/nāṟ‐col/) in the śāstric descriptions of Tamil

The research for this article, which falls under the general category "History of Linguistics", was started as an examination, in context, of the use of the Tamil technical term tiricol, lit. "mutant word", which is the designation of the second among four categories of "word(s)" (col) inside one of the two quadripartite classificatory systems, found in the Tolkāppiyam, an ancient Tamil śāstric text, probably dating back to the first half of the first millenium AD. The first term in that quadripartition is iyaṟ‐col "natural word", whereas the third and the fourth are ticai‐c‐col "regional word(s)" and vaṭacol "northern word(s)"