Choosing the Set of Renderable Strings

[James Kass via Unicode]

I wrote,

> Changing the entry order to:
> ᨽᩮᩣᨾᨶᩣᩮ
> <LOW PHA, SIGN E, SIGN AA, MA, NA, SIGN AA, SIGN E>
> ... forms the NAA ligature and the vowel re-ordering matches the
> Lamphun graphic you sent.  But that kludge probably breaks the
> preferred encoding model/order.

On the other hand, do the script users normally input the NAA ligature
sequence first and then add any additional signs or marks?  If the
users consider NAA to be a distinct "letter", then that might explain
why a font developed by a user accomodates the ligation for the string
"NA" + "AA" only when nothing else appears between them.  If, for
example, there's a popular input method or keyboard driver which puts
"NAA" on its own key, then the users will be producing data which is
"NA" plus "AA" plus anything else.