Understanding the relative chronology of implosivization in Thai and Khmer, and how it interacted with the development of the scripts, is difficult (at least for me). In this answer it is suggested that the less complex letter developed from the more complex. This seems odd prima facie, and out of step with the other extra letters developed in Thai which all added material rather than taking away (e.g. ฟ from พ). Am I missing something here?

  • Isn't บ an extra letter, and isn't it derived from ป by taking material away?
    – rchivers
    Commented Mar 28, 2020 at 17:44
  • 1
    What strikes me is that the extra character is simpler when comes before the Sanskrit character (so to speak), and more complex when it comes afterwards. That's quite elegant and would go quite a long way to explaining why the Sanskrit characters were simplified in some cases, if you assume that there was a logic to where they were inserted (seems to me there was). What is puzzling is why some of the Sanskrit characters were that complex in the first place e.g. why have the dip in ต if you don't need to distinguish it from ด?
    – rchivers
    Commented Mar 28, 2020 at 17:55
  • 1
    Maybe what really happened was that ด initially had the value of ต and the shape was changed to free ด up, i.e. to create a slot for the native /d/ sound.
    – rchivers
    Commented Mar 28, 2020 at 17:57
  • Your first comment: At least the answer that I cited claims that, yes. (And it seems similarly odd.) I don't quite understand your second comment, although I agree that there was certainly logic to where these characters were inserted (assuming alphabetic order has stayed the same down the years). As for why they were that complex in the first place, yes, that's another way of asking my initial question…maybe it's because it was modelled closely on the Khmer character, but I don't know.
    – legatrix
    Commented Mar 28, 2020 at 20:53
  • 1
    I think so, or in more practical terms so that you have a 1:1 transliteration. The same philosophy gives you the ษ in อังกฤษ or the double ต at the end of แมตต์ = Matt - i.e. it should be possible to recover the original orthography even though the pronunciation changes. I must have misremembered the Brahmic order (should have been obvious from the A you linked to). I'm not sold on the idea that alphabetical order would have been decided on the basis that implosives counted as unvoiced - we may be able to see a connection in hindsight, but it's a lot of foresight to ascribe to whoever it was.
    – rchivers
    Commented Mar 29, 2020 at 10:25

1 Answer 1


The Thai letter ด would not have been derived from the Thai letter ต. Both letters were introduced at the same time when the Thai alphabet was constructed (in the 1200s in Sukhotai).

When the Thai alphabet was devised, it served two main purposes. One was to be able to write Thai words and the other was to be able to write Sanskrit (or Pali) words. The Thai alphabet has one consonant symbol for every Sanskrit consonant sound and a few extra symbols, presumably for Thai sounds which did not occur in Sanskrit. Many of the spoken sounds produced by the consonant symbols have changed over time (the shapes of many Thai letters have also changed over time, but the particular letters ด and ต have not changed much since the 1200s).

The symbol ด (which is now pronounced like the English d) was not one of the symbols which corresponded to a Sanskrit sound. The symbol ต corresponded to the Sanskrit sound t (an unvoiced, unaspirated stop, with no English equivalent) and it is still pronounced that way today. I do not think anyone knows for certain how the symbol ด was originally pronounced, but the most plausible guess (in my opinion) is that it was pronounced as a glottal stop followed by an unaspirated t or d.

The Thai letter ท corresponded to the Sanskrit sound d (a voiced, anaspirated stop), and it was probably originally pronounced like the Sanskrit d (which is the same as the English d), but it is now pronounced like the Sanskrit th (an unvoiced aspirated stop, which sounds like the English t).

  • Well yes, but by that logic ฟ was not created from พ either, and the Q does not make sense. I think the Q does make sense and you have to interpret it as asking whether ด came from the precursor of ต, even though it does not follow the same pattern as most of the other added letters (where detail has been added rather than taken away). It might be worth noting that Tai Tham has no ด (it co-opts ฑ) but the equivalent of ต (ᨲ) seems to have something corresponding to the notch. For me that supports the idea that ด did come from (the precursor of) ต.
    – rchivers
    Commented Jan 8, 2021 at 6:05
  • 1
    Yes, ฟ was not created from พ either, but both were inspired by the same precursor (from the old Khmer script, which corresponded to the Sanskrit consonant sound b). The scripts (such as the old Khmer script) which inspired the original Thai script (in the Sukhotai era) had one consonant symbol for each Sanskrit consonant sound. The Thai script added additional symbols (presumably for additional sounds which did not occur in Sanskrit).
    – snew
    Commented Jan 8, 2021 at 17:57
  • 1
    There are a number of pairs of Thai symbols, such as ข,ฃ and ค,ฅ and ช,ซ and ด,ต and บ,ป in which both symbols were introduced at the same time and both derived from the same precursor (in old khmer, and other scripts). In each pair, one of the two symbols corresponded with a Sanskrit consonant and the other corresponded to a presumably related Thai spoken sound.
    – snew
    Commented Jan 8, 2021 at 17:58
  • I agree with you that it is difficult to explain the consonant pair ฎ,ฏ (these letters looked different in the original Thai script). The letter ฏ was used to represent the Sanskrit retroflex unaspirated T, but as far as I know the retroflex letters were never used in spoken Thai, so I cannot guess what sound the letter ฎ would have been needed for. Unlike the other pairs which I listed above, where each pair of Thai letters corresponded to a single letter in the old Khmer script, this pair of Thai letters corresponds to a pair of old Khmer letters.
    – snew
    Commented Jan 8, 2021 at 19:15
  • I think there are a lot more twists and turns than you are allowing for there. The fact that ซ was created from ช suggests if anything that สศษ were pronounced more like ฉ at the time (unless you think that there were native words beginning with a plain /s/ but none of them had low or rising tone). The oddity of ฎ has been pointed out a few times but I think the reason for it is lost in the mists of time. Also there are several words of S/P origin that are spelt with ด, which complicates the picture even more.
    – rchivers
    Commented Jan 9, 2021 at 3:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.