Why is Sindarin and Quenya not available on Duolingo?

Someone seriously needs to get Sindarin and Quenya on Duolingo!! Even though I know that the language isn't officially complete, can't they just put what they know on their site to help people learn it?!?

The problem is not just that nobody signed the languages off as complete, but that - depending on the certainty you need - we actually know relatively few things about Quenya and Sindarin:

1. Much we know is conflicting and people won't necessarily agree how to resolve those issues. As an example, here are a couple of quotes from Tolkien about negation:
   • Delete √AL|LA “not”. Quite unsuitable. AL, LA have already too much to do.
   • û will not do. [...] The negative lá simply denies that the positive statement is true in fact.
   • ú should remain, but with the sense “bad, uneasy, hard”
   • Back to ú. lá can be beyond ... ū should be negative particle
2. Tolkien's notes are not published in full yet, which makes everything we think we know preliminary, e. g. it was once thought that the regular past of a verb like nor- should be norn based on early evidence, but it turns out that there was a conceptional shift on Tolkien's part later that makes its regular past onur in Sindarin.
3. Many things aren't known explicitly but are inferred from the examples we see, and people disagree on how to interpret those.

That all means that duolingo isn't really a good medium to present Tolkien's languages in an adequate way with all their revisions, conceptual vacilation, contested hypotheses and vocabulary gaps. I honestly don't understand why it needs to be duolingo: people have written good resources about both Sindarin and Quenya (Atanquesta, Gelio Edhellen, Eldamo), there are discussion and study groups etc.

Another thing: creating a course about Elvish is comparatively doable, but maintaining it is hard, because with every new publication of source material, you need to update it, sometimes in radical ways, e. g. when we'll get more information on pronouns (which we hopefully will in a couple of years), that will affect practically every lesson. Fighting all the outdated Elvish on the internet, whose authors abandoned their projects (after 15 years or more of dedicated work mind you; "I promise, I won't stop" really doesn't help because much can change in that time span), already is a major problem, but when a seemingly official course (another thing many experts aren't going to like) on duolingo gets outdated, it'll be especially worse.