Page 174 - The International Journal of the Royal Society of Thailand Vol.XIII-2021

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

Group 1: the Mid-Class

Consists of 5 voiceless unaspirated stop consonants and 2 voiced unaspirated
stops; this group has 9 consonant letters.

Table 4: the Mid-Class consonant letters

vl unasp stop vd unasp stop

1 2 3 4 5 6 7

k c t p  d b
ก จ ฏ-ต ป อ ฎ-ด บ

Group 2: the High Class-1 and the Low Class-1

Consists of 4 voiceless aspirated stop consonants and 3 voiceless stops;
there are 24 consonant letters in this group consisting of 11 the High Class letters
and 14 the Low Class-1 letters.

Table 5: the High Class-1 and the Low Class-1 consonant letters

vl aspirated stop vl fricative

1 2 3 4 5 6 7

kh ch th ph s f h
High-1 ข-ฃ ฉ ฐ-ถ ผ ศ-ษ-ส ฝ ห

Low-1 ค-ฅ-ฆ ช-ฌ ฑ-ฒ-ท-ธ พ-ภ ซ ฟ ฮ

Group 3: the High Class-2 and the Low Class-2

This group consists of 3 voiced nasal consonants and 4 voiced semi-vowels.
There are 18 consonant letters in this group consisting of 8 letters of the High

164 The Thai Writing System: Reasons behind Its System