2.2 Vowels
Monophthong
In English, there are twelve monophthongs while Thai has eighteen pure vowels. This is advantageous for Thai as there are only two vowels which does not appear in Thai; they are [ə] and [ʌ]. Therefore, Thai students have little trouble pronouncing most English vowel sound.
However, for English native speakers trying to pronounce Thai vowel sounds, [o] and [μ] seem to be difficult for them since they do not occur in the English sound system.