Thai Vowels, Diphthongs, and Their Transcription
jump to monophthong chart
jump to diphthong chart
jump to /j/ glide ending chart
jump to /w/ glide ending chart
This is one of the most important reference pages at thai-language.com
. Students studying Thai often spend
a great deal of time learning the Thai consonants, while the vowels may get only a cursory look. Maybe this is
because, unlike the consonants, the Thai vowels are not organized into a well-known pattern, with
objects and children's rhymes.
The vowels of the Thai language can be intimidating at first, especially when students learn that
there are sixteen different vowel symbols that combine into different patterns. But many of the combinations
make sense once you get the hang of it and the system can be mastered with a little dedication.
In Thai phonology, there are nine basic vowel monophthongs
. Each of these is pronounced with either a short
or a long
a total of eighteen simple vowel sounds. We'll present these first, and then discuss the few diphthongs
that Thai uses.
But first, please note that in English the terms short
speaking of vowels) sometimes refer to a certain grouping of vowel qualities
(a distinction more properly referred to by the
), whereas in our discussion we will be using the linguistic meanings,
where "long" and "short" refer to the relative length of time for which the vowel is pronounced.
This feature, vowel duration
, is not contrastive in English; for example, you can say, "ball" quickly
or draw out the vowel, "baaaaaaall", and—while it may sound strange—the word still has the same meaning. In Thai, you must use
the correct duration, or you might not be understood. For more information on this, please check the
In addition to having long and short forms, each basic vowel sound can appear in an open
syllable. This means simply whether the vowel finishes (i.e. completes) the sound (open) or there is a final consonant tacked on (closed).
Now we can proceed to the table of basic vowel sounds. Each of the nine basic sounds is shown for all four possible
combinations: short-closed, short-open, long-closed, and long-open. The second line of each sound shows an example
Thai word for each case.
|Short/Long, Closed/Open forms of the Nine Basic Monophthongs of Thai
|ประชา ||bpraL chaaM
||เทวี ||thaehM weeM
||เ-อ (5.) ||-uuhr
||โมโห ||mo:hM ho:hR
||จุฬา ||jooL laaM
Next we have diphthongs
, which are vowels that are pronounced as a glide between two monophthongs. In Thai, the second vowel of
a diphthong is always -ะ /a/
. There are three diphthongs in Thai (Tingsabadh and Abramson 1993, Iwasaki 2005).
If you see that some other books list many more diphthongs, then they are probably counting the live consonant endings /y/ and /w/ as diphthongs (or triphthongs).
Here, we opt for the simpler analysis and then list the glide endings /y/ and /w/ separately below. This approach is simpler because
the nine vowels and three diphthongs listed in these two tables form the complete set of vowel phonemes
As mentioned above, we have now listed all of the vowel phonemes
of Thai; all of the sounds below this point are variations on the vowel
phonemes listed above. Another objective of this page, however, is to present
a complete reference on the ways in which the vowels of Thai are written in Thai. For this, we need to continue on with a study
of the glide endings and two special vowel symbols, because there are some special vowel symbols that haven't appeared yet, and because there are some
unexpected ways of combining vowel graphemes
4. Glide Endings
Five of the nine monophthongs and two of the three diphthongs can appear with the glide ending consonant /y/ (IPA: /j/
), which sounds like the
high, front vowel /Y/
. The open/closed syllable distinction is not shown in this table because none of these combinations can accept a further final
consonant. In our analysis of these as consonant glides, that makes sense, because these syllables are already "closed" with the glide consonant.
And this treatment is further confirmed by the fact that, if you did prefer to think of these as additional diphthongs and triphthongs, you'd
have to explain why they can't accept a final consonant: there's no sound such as /doyk/
|/j/ Glide Endings of Thai (with example words)
|-ai (3., 8.)
||ไ- [usually short]|
||อ็อย [rare] ||-awy
The glide ending /w/ can be used with five of the nine monophthongs and with the diphthong /ia/. As with the glide ending /j/,
note that some of the duration contrasts are not attested. By now, you have probably noticed that our phonemic transcription does not
adhere to this treatment of glide endings. There are two reasons for this. The first is that the system was developed a long time ago,
before I was aware of this simplification. Secondly, such a system has to accomodate equally the phonology of Thai and the phonology of the
learner's English; it was originally designed with the singular goal of allowing a beginning student to approximate Thai phonemes, without
consideration for capturing important phonological generalizations of Thai.
|/w/ Glide Endings of Thai (with example words)
||เ-า||-ao (3., 8.)
||เ-อว [rare] ||-uaaw (7.)
5. Miscellaneous Vowel Orthography
To complete our discussion of the vowel graphemes
used when writing Thai, we list the last two symbols that haven't appeared.
The first one combines the simple monophthong /a/ with a closing sonorant, the consonant /m/. We'll put this in the "closed" syllable
column, since it can't accept yet another consonant. Finally, there's the "ligature" shown in row 27, which combines the initial consonant
/r/ with either /ɯ/
|Two Miscellaneous Vowel Glyphs (with example words)
||อำ||-am (3., 8.)
||ฤๅ [rare] ||reuu
phreutH saL jikL
|ฤดู ||reuH duuM
||ฤๅษี ||reuuM seeR
is a special-case way of writing /a/.
3. For the purposes of the tone rules
, most short/open vowels generate a dead syllable, however the short/open vowels marked (3.) are treated as a live consonant ending
4. Acts as a low-class consonant.
5. Can also be used in a closed form for certain foreign loan words: เทอม
7. Only appears in the example word shown, and is not really so much a word as it is a sound.
8. In a high-tone syllable (i.e. low-consonant class and ไม้โท
tone mark), this vowel sound may be pronounced short
when followed by at least one syllable in compound words and long
when alone or in final position.
9. When the ไม้เอก
tone mark appears in a live syllable with แ
-- and a mid- or high-class initial, the syllable has a short vowel sound. Examples: แต่ง
10. When any tone mark appears with เ
--, or in some rare cases, such as เพชร
, the syllable has a short vowel sound. For more information on this, please see Words With Irregular Pronunciation
11. Some words using อิ
are pronounced with short -ee. For example, หิมะ
/. In fact, even in cases where our transcription is /-i/ (as in the English word 'hit'), the sound is better approximated as somwhere between /-i/ and /-ee/.
For more information on this, please see Words With Irregular Pronunciation
Iwasaki, Shoichi, and Ingkaphirom, Preeya. 2005. A Reference Grammar of Thai
. Cambridge: Cambridge University Press.
Tingsabadh, M.R. Kalaya and Abramson, Arthur S. 1993. Illustrations of the IPA: Thai. Journal of the International Phonetic Association
23(1). Cambridge: Cambridge University Press.