Appeal to ISO 639 RA in support of Elfdalian

[Shawn Steele]

> > For my part, I think it wiser not to push the RA in a direction that this list might later come to regret.

> Can you give any substantiation to this?

Substantiation?  I'm not sure how you substantiate a hypothetical.

However, I could see registration of a subtag here causing them to think the problem's solved and punt it or avoid it.  (I don't know the people so I don’t know how likely that is).  Additionally, some have expressed concern that the tone of poorly chosen letter could be off-putting to them, which could cause them to become more defensive of their position, &/or create a feeling of ill-will that could make it harder to work with them in the future.

-Shawn