I'm afraid Yanclae is talking about something very different as you are aiming for, Jeremy.
You want to create a possible elfin language - taking what you find in the names and the stories. An ambitious fan project to add something to the Pini universe that isn't there so far.
Yanclae - as I understand it - is talking about an actual elfin language that would be when Wendy's wonderful creation would exist for real somewhere.
I love your imagination, Jeremy, and the way you are putting this puzzle together! And I hope, that the fun in it will stay with you! Don't let discourage yourself! I'd like to read more about it and be a curious, admiring follower of this thread - doubt to be of any help, though.
About the communitcation sphere the Wolfriders found I remember a discussion some time ago. Were you around and part of it, jeb (too lazy to look it up )?
There were mainly two reasons given for the "not understandable" message:
1. The sphere was damaged - and so was the message, scrambled and mutilated.
2. The message was standardized for the Conheads (and their hive mind) - too "intense" for the recent elves. Too condensed, too loud, too high pitched.
Probably a mixture of both.
About Humans being (un)able to learn the elfin language - I remember Lehrigen was speaking it pretty well, Trollhammer. It was mentioned somewhere in the HY story arc, I guess. When it's of any interest I'll hunt down the proof - or correct myself.
P.S.: A plea. Jeremy - would you mind formatting longer posts with some paragraphs and spare lines? Reading through a huge cluster of text is always hard.