There are 44 consonant symbols in the Thai alphabet which produce 21 initial consonant sounds when used at the beginning of a syllable and 6 final consonant sounds when used at the end of a syllable. There are 24 low class consonants (shown in green below), 9 middle class consonants (yellow), and 11 high class consonants (red); the classes are important for determining the tone which a syllable should be spoken with. Since many of the consonants produce the same sound, each consonant has an acrophonic word that is conventionally used to uniquely identify it.

The initial and final phonemic transcriptions given below are used consistently throughout Thai-language.com when the default transcription option is selected in the site control panel.¹ Our system uses /g-/ instead of /k-/ or /kh-/ for the Thai consonant ก, but remember, in Thai, a /g-/ sound is always hard. In English it can be either soft (as in gentle) or hard (as in grapple).

School-aged kids in Thailand learn the alphabet by memorizing the Thai Alphabet Poem.

Initial Consonant Phones

In Thai, there are twenty-one consonant sounds which may occur at the beginning of a syllable. Any one of the forty-four Thai consonant graphemes can be used in syllable-initial position. The 21 sounds can be divided into three types according to their phonetic characterics: sonorant, plain, and aspirate. As you can see in the following table, doing so will help you remember the consonant class of each consonant grapheme. This information is required for applying the Thai tone rules.

Final Consonant Phones

In the alphabetical listing above, note that the following consonants never appear at the end of a syllable: ฉ, ซ, ผ, ฝ, ห, ฮ. These are marked with n/a in the "final sound" column. Three others act as vowels or dipthongs (combination vowels) when they occur at the end of a syllable, and they are marked with vowel in the "final sound" column: ย, ว, อ.

The following chart summmarizes the six final consonant sounds. Three of these are live consonant endings and three are dead consonant endings. This distinction is important for the tone rules. For more information, see the Consonant Endings reference page. (The two obsolete consonants are grayed out)

Notice that the live ending consonants are the same as the initial consonants from the 'sonorant' initial-consonant group (minus ว and ย, which are considered live-ending diphthongs).

Learning the Classes of Consonants

Sooner or later, you'll have to memorize which class every consonant belongs to so that you can apply the tone rules. There are many ways to approach this studying task. For example, here's a Thai schoolchild mnemonic for remembering the mid-class consonants:

Or, for a detailed linguistic treatment, please refer to Richard Wordingham's article, Phonetic Organization of the Thai Consonants.

The easiest method for me was to study the characteristics of the consonant sounds, as sonorant, plain, or aspirate, as shown in the table of initial consonant sounds above. This method is detailed in the following lesson: Phonemic Approach to the Consonant Classes.

If you prefer a memorization-oriented method, you might practice and memorize the alphabet with the proper tones on the acrophonic words. Read on to see how to use tone rules to find the tone of any word by memorizing the tone of some of the sample words listed above.

What follows are some simple observations about the classes of consonants. Notice that the อ aaw sound for high-class consonants only is pronounced in a rising tone, as denoted by a superscript 'R.' (The อ aaw sound for mid- and low-class consonants is pronounced in a mid tone). By always practicing saying the letter names with the proper tone (even though the corresponding sample words may have different tones), you will form an association between the letter name and the correct sound. Then you'll know the high-class consonants by sound. Another clue to the high-class consonants is that none of the sample words for these consonants are spoken with a mid or high tone—most have a low or rising tone.

Next, after eliminating the high-class consonants, note that if the sample word is pronounced in a low tone, then the consonant must be mid-class. The four remaining mid-class consonants, whose sample words are pronounced in the mid tone, can be memorized: จ /jaawM jaanM/ (plate), ฎ /daawM chaH daaM/ (dance hat), ป /bpaawM bplaaM/ (fish), บ /baawM baiM maaiH/ (leaf). For the latter, note that the second syllable has a rising tone but it is the first syllable, pronounced in mid tone, which contains the letter in question.

At this point you could simply remember that the remaining consonants are low-class, but we can make some observations about them also. For one thing, none of the sample words for the low-class consonants are pronounced with a low tone. Also, of all the sample words, there are only three which use the falling tone. One of them is ผ /phaawR pheungF/, which we know is high-class. The other two, ซ /saawM so:hF/ (chain) and ฒ /thaawM phuuF thaoF/ (old man), are low-class.

For more information on consonant classes and how they affect the tone of a word, see the section on tone rules.

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1. Transcriptions shown on this page use the 'Thai-language.com enhanced phonemic transcription' scheme regardless of the romanization settings in your site control panel.
2. The acrophonic words for the two consonants ฃ and ฅ do not include the actual letter itself. This is because these two consonants are considered obsoloete; they are no longer used.