It may be that 10646.2 diverges from this, lacking access to a copy of the
spec
for 10646.2 I cannot say, but I have been told that 10646.1 is point/point
equivalent to Unicode, so it should have preserved this distinction.
What a confusion.
First of all, what you refer as "10646.2" should be DIS 10646-1.2.
Moreover, it is both DIS 10646 and Unicode which are changed so that
the 16 bit form of IS 10646 is expected to be equivalent to
the latest version of Unicode.
Then,
And if 10646.2, in fact, adheres to this layout of Devanagari, then
disambiguation is only needed for Han,
Devanagari, in narrow meaning not Devanagari family, is used for, as far
as I know,
Hindi
Sanskrit
Marathi
Nepali
As long as the display of characters (with the definition of Unicode)
concerns, there is no need for language distinction.
But, it is not enough.
The problem is that ligating rules are different language by language.
So, if you want to display ligated forms correctly, you can't do so
without language information. It should be noted that, unlike "fi"
ligature, ligating in Devanagari is of vital importance.
Anyway, I don't think detailed profiling of ISO 10646 is necessary
here in MIME ML. So, we should just accept the fact that it needs
further profiling.
If you need any other information on Devanagari, ask it by private mail.
Masataka Ohta