The similarities among Thai characters is one of the reasons a Thai reader who can read without stumbling is rare. The biggest reason is the lack of spaces between words (and this is one of the reasons these character classes would be so helpful, as they could help with word-splitting or syllable-splitting Thai text). I've never heard of a Thai speed reader, and I do not believe it is possible. That said, there is definitely a difference between the otherwise similar characters in usage and in pronunciation; and experienced readers will be able to guess the word without seeing the minute details. Others, like myself, prefer to have a larger font size so as to see those minutiae more clearly.

None of these issues, however, affect the script at present. I have gone over the codepoints with a virtual fine-toothed comb, rechecking all of them. I did make a couple of corrections in the process, one minor one being the removal of the unassigned codepoints from one of the code blocks. There remain some edge cases which the script does not address--perhaps in the future a Thai linguist of superior skill might suggest additional functionality.

I feel more comfortable with the Thai side of this script, at present, than with the Perl side (which simply refuses to work). It is to contribute to the Thai programming community that I do this; and I much appreciate the Perl gurus who are able to help on that side of things.