Page 172 - The International Journal of the Royal Society of Thailand Vol.XIII-2021

The International Journal of the Royal Society of Thailand
Volume XIII – 2021

There are multiple pairs of similar consonant letters that can be explained in

either way. The case for ด-ต, บ-ป, ฎ-ฏ has been explained. As for ท-ฑ which look
similar because they share a voiced unaspirated stop but different places of
articulation, the letter ท is a dental stop but ฑ is retroflex. For ล-ส are both dental

but the difference is that ล is a voiced semi-vowel whereas ส is voiceless fricative.

4. Classification of Thai Consonant Letters as High, Mid and Low class

Because Sanskrit consonants are classified in phonological order as stated in

section 3, the inventor of Thai consonant letters has adopted the same concept in
both ordering and classifying Thai consonant letters. Even with 10 additional
consonant letters we have still kept the same logic in ordering and classifying to

that of Sanskrit. As such we can see that even though we divide consonants into
three groups which are the High Class, the Mid Class and the Low Class, the High
Class and the Low Class are sub-categorized into High Class-1 and the High class-2
like the Low class-1 and the Low Class-2. All of these classes of consonant letters

still have the logic of phonology behind them which we will discuss later. The three
classes of Thai consonant letters as stated are in table 3 as follows:

162 The Thai Writing System: Reasons behind Its System