You don't have to listen to authentic Thai for very long to realize that comparatively few words are pronounced with the dictionary tone.

All the learning material out there seems to be focused on helping people produce individual words with the supposedly correct tone - but this is only half the picture as I now see things. You also need to understand how the tone system works at sentence level. So far, I have not found anything on this.

What I've noticed myself is that while many syllables are not given their dictionary tone, this doesn't mean that they default to mid/neutral tone, or that their tone is arbitrary. The overall system seems to be that some words have greater weight within the sentence, that those words are given their dictionary tone, and that the tones of the intervening words - I've been calling them interstitial tones for now - are mainly a matter of setting up or recovering from the tonal gestures required by the heavier words.

Obviously, if that's right, it's important to know which are the heavier words.

I am sure this subject must have been investigated before and was wondering:

Whether there is something better than 'interstitial tones' that I could use as search term;

How much of a parallel there is between a word being given its dictionary tone in Thai and a word being stressed in English.


2 Answers 2


Tone sandhi is the term you are looking for.

According to Wikipedia,

Tone sandhi is a phonological change occurring in tonal languages, in which the tones assigned to individual words or morphemes change based on the pronunciation of adjacent words or morphemes.

See also this question and my answer for it (pay attention to the links within):

  • I ought to mention that the second paper linked to by user6726 denies that Thai exhibits tone sandhi. Still, it does seem to be what I was describing in my original post.
    – user23078
    Nov 9, 2018 at 14:38

Well, I am also very interested in the issue of tone sandhi in Thai, as I have just started learning Thai. I do speak Mandarin, and have spent 15 years studying the language, and am very familiar with the concept of tone sandhi and how it works.

Here are my 2 cents worth on Thai. Keep in mind that I have only been learning for two weeks, but because of my familiarity with the issue, I am listening very VERY carefully to the recordings on Mango language Thai. Here are two observations (and I would love for someone with real experience with Thai to either confirm or deny these).

First: in Chinese, rising and falling tones are constant throughout the syllable, that is, as soon as the utterance starts, the rising (or falling) tone starts, and continues for as long as the syllable is uttered. From what I have heard in the Thai recordings, this does not sound like it is the case at all.

In Thai, the syllable can be spoken on a flat (high or low) tone, and the actual movement of tone is saved for the very end of the syllable. Or, pictorially, a rising and falling tone in Chinese versus Thai:

           Chinese                          Thai
              /    \                                    falling
2nd tone     /      \ 4th tone          rising     /   ________                 
            /        \                       _____/            \

2nd observation: I am hearing clear tone sandhi when I listen to the native speaker say puut2 daai2 (I can speak). The word puut2 when spoken by itself has a clear falling tone (albeit with the "fall" in tone reserved for the end of the syllable). When I hear the native speaker say puut2 daai2 (which should be two falling tones), the first word puut2 is clearly spoken on a level tone with no falling, and the second word has its falling tone. To my mind, this is very analogous to the Chinese tone sandhi for the second tone, which can remain at 1st tone level if it is preceded by a first tone: ta1 lai2 kan4 wo3 => ta1 lai1 kan4 wo3. That is, the first word puut2 does not need to fall because the second word daai2 would just have to start at a high tone again.

Anybody out there to confirm (or deny) this?

  • Your observation is valid, but these are two different phenomenons. One is neutralization (elision, reduction) which occurs in all languages one way or another. And the second phenomenon is when the tone is changed, usually, to an "opposite" one, as it happens with 谢谢, 不买, and 一次. Mar 13, 2023 at 20:39
  • Thanks, good point. I see what you are saying -- the Thai tones are not actually being transformed into ANOTHER Thai tone, simply being clipped off at the falling part. This is very clear in the recording of "puut(F) mai(F) koi(F) daai(F)" (I can barely speak) -- all falling tones that remain at high level except the last one.
    – Alan
    Mar 15, 2023 at 11:50
  • Though I must say that with the "clipped" falling tones (that remain at high pitch), I am not sure there is any way to distinguish them from high tones. High tones start at a high pitch and often (sometimes) rise from there. Sometimes they don't rise at all. So how to distinguish between a falling "clipped" tone, and a high (non-rising) tone. Sound the same to me. And if a falling tone is becoming a high tone, why wouldn't that be tone sandhi?
    – Alan
    Mar 15, 2023 at 12:04

Your Answer

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