Perhaps we should ask for a Class A liaison with SC 4, and offer
our version as the next ISO 639 variant? :-)
In my opinion, I don't think we will see much usage of either
the ISO 639 three-letter codes or the sublanguage schema.
It is important that they are there for those times when it is
vital, but it is more important that we have a specification
that is generally available for the 2-letter codes.
The idea that we must change our Standard just because ISO has done
something they should have done already in a way incompatible with
our way is, IMHO, quite unpleasant.
Unpleasant but unavoidable, I think. I will be quite certain that
the reference to ISO 639 includes the year of issue, so that we only
have to change our standard if we *want* to access the new information
in a future version.
Given the degree of slowness over the 3-letter codes, I don't imagine
that keeping up with ISO will be an overly ardous task.
Harald A