Richard Wordingham wrote:

> Browsing through the Unicode mailing list, I noticed a remark by Peter
> Constable that the Thai collation order had been changed by removing
> its dependency on how a word was pronounced. I'd like to hear more
> about this change, e.g. its date.
> [...]

Why not asking this on the Unicode List itself?

Seems to me that a very technical IT question about the internals of the
Unicode standard is more appropriate on a forum about Unicode than on a
forum about writing systems in general. As you said, there is nothing
special in the Thai vowel marks themselves: the peculiarity is the way they
have been encoded in the Thai block in Unicode.

--
Marco