The definition of the intonation of a Thai syllable plays a fundamental role. A word pronounced with the wrong tone can have a completely different meaning.

The following table demonstrates this on four words:

In these examples the tone marks alone determines, how a word must be spoken, in order to give the desired meaning.

In other words, it may be that they are spelled differently but have the same sounds. While listening to so they can be classified correctly only by the sound:

These examples demonstrate the importance of correct pronunciation including tone pitches. If a word is pronounced incorrectly, their meaning changes completely. A wrong emphasis does somtimes lead to embarrassing or cheerful situations. Because the set of Thai tone rules seems to be difficult manageable at the beginning, I can only recommend to listen to the examples over and over again, until the words as a whole, ie including the correct pronunciation are learned

The smallest unit of speech in Thai is the syllable. The intonation has to be therefore calculated on syllables.

A syllable can be spoken in high, low, rising, falling or in a medium tone. More about the pitch can be found here.

How a given syllable is pronounced can be derived on the basis of fixed rules of the written word. There are however several factors that need to be considered for a determination of the pitch. It is therefore necessary to examine:

1. What is the class of the initial consonant?
   Consonant classes are described here. Further details will follow on this page below.
2. Is it a short or a long vowel?
   Details on vowels are described here.
3. Is it a living or a dead syllable?
   What is this, see below on this page.
4. Is a tone mark to take into account?
   More about tone marks here. How they are applied is the topic of this page.

In principle, any Thai syllable starts with (at least) one consonant. For now, we restrict to those syllables that have only a single initial consonant.

One of the criteria by which the emphasis of syllables is determined is the membership of initial consonants to one of three classes: Middle, High or Low.

If consonants are referred to individually they are spoken together with a long a:w. Thus the answer to criterion 2 is "long". A "living syllable is it also (criterion 3), and a tone mark (criterion 4) does not exist. Thus the emphasis is such, as you have heard before by listening to the consonants.

I am aware that here I had to prejudge the criteria 2-4, we have not yet discussed. Therefore, now the rest of the definitions.

Length of the vowel (2)

Most vowels exists in a short and a long version. To determine the vocal length we would probably make the least difficulty. Together with an initial consonant from the low class (and only there) a syllable may be pronounced differently depending on the length of the vowel. We'll come back to this point.

This may sound a little cruel. But you will never be in need to kill a living syllable - you can always take one that is all ready dead!

What is meant is that if a syllable ends abruptly (dead syllable) or can linger (living syllable). Lingering is a syllable as if it ends in a long vowel. If you say kha: or khaaaaa: - it is still a long vowel and a living syllable.

After a short vowel as in kha is quite fast final, because otherwise it would become a long vowel. A syllable with short vowel and without a final consonant is called therefore "dead".

Even with a so-called nasal น, ณ, ม or ง a syllable is lingering. At a word like na:m you can "hum" the "m" sound if you want without altering the meaning.

Also "dead" is a syllable if it is ended with a so-called plosive. A K-, P-or T-sound at the end of a syllable is closing the sound, there is nothing that could be drawn out.

In the following table are detailed examples of the two syllable types listed. Note that on one line very different tones may appear. The type of the syllable is merely one of several criteria.

A syllable may or may not have a tone mark. Only at initial consonants of the middle group, all four tone marks are used. For the high and low consonants are only the first two applicable (MAI EEK and MAI THOO).

* Depending on the class of the initial consonant
** Only for middle-class consonants

The following generally applies: If an tone mark is given, then it determines the pitch together with the class of the initial consonant. If none exists, type of the syllable and vowel length must be considered too.

After we have clarified the terms in the previous sections, here is a table that addresses all four criteria. There are examples of each listed.

Here you can see that the tone rules for the 3rd Class are uniformly, no matter whether they are paired or unpaired consonants. They are therefore listed separately because only the consonants of group 3.2 (unpaired consonants) can be preceded by HO HIP or O ANG, and are treated then as if they were part of their classes.

The four examples in a preceding O ANG are the only words with this prefix.

With double initial consonants a distiction is made between preceding and consecutive consonants. The difference is whether the two consonants together can be pronounced or not. Preceding HO HIP or O ANG from previous section ar not included here, because they are not pronounced as consonants. Learn more about double initial consonants here.

With consecutive consonants these combinations are meant, either spoken together (true cluster) or changed as a single sound (false cluster).

Only if the first consonant of a cluster is one out of ก, ข, ค, ต, ป, ผ or พ followed by ร, ล or ว, they can be true clusters. But even here, not all combinations are possible, as the following table shows:

These true clusters are handled by the tone rules of the first consonant.

For false clusters like these in the following table the tone rules of the spoken consonant are valid:

All other cases of double initial consonants are prefixed consonants. Such syllables are pronounced in two syllables, after the first consonant a short "a" is inserted. The following tone rules for such clusters are determined: