text: 1999 version The 1999 version restored the distinction between the transcriptions of the pairs อึ  and อุ  and เอือ  and อัว . It also simplified the transliteration of final ว , which now is always transcribed .
  Allowed variants
  The following variants have been allowed:
  Criticism
  The system does not transcribe all features of Thai phonology. Particularly it has the following shortcomings:
  It does not record tones.
  It does not differentiate between short and long vowels.
  The notation  does not differentiate between IPA  and IPA  (see table below). Using  for  would have been more consistent with the other stops and is used as such in ISO 11940-2.
  The notation  does not differentiate between IPA  and IPA  (see table below).
  The original design envisioned the general system to give broad details of pronunciation, and the precise system to supplement that with vowel lengths, tones, and specific Thai characters used. The ambiguity of  and  was introduced in the 1968 version.
  The system is confusing for English speakers and leads to constant mispronunciation. It is a technical system rather than a practical system. For example in a practical system ผ, พ and ภ would be transcribed as  while ป would be . Similarly ท would be  and ต would be  while ค would be  and ก would be . The idea of using  to represent aspirated sounds is totally confusing for general use. Finally จ would be more clearly transcribed as .