Our green haired Fairies including Meri Greenwood speak what the people of Niarg know as Archaic Modern Niarg, the ancestor of what they were speaking at the time of our epic tale. It sounds like some sort of Germanic or Nordic language, yet it is quite easy to understand and it makes the Fairies come to life.
What Archaic Modern Niarg happens to be is Middle English with most of the obsolete words eliminated so that the uninitiated modern reader can read it without difficulty. It is no harder to read than a note full of misspellings passed by grammar school kids, yet it would be understood at once by people in the London area, six hundred years ago, since we have based its spelling, grammar and word order on the writings of John Wycliffe and Geoffrey Chaucer.
Thirty years ago, I learnt to read Middle English using the rules of pronunciation based on a vowel shift which was thought to have occurred by the widely respected E. T. Donaldson and others, which made the language patently incomprehensible to the ear, and made Chaucer's poetry not rhyme very well. As a Botany major, I had no stake in revering his work and I didn't think he supported his claim very well. So, I started reading it with Appalachian vowels and found that it not only rhymed much better, it was now easy to understand when one listened to it.
When I read some Middle English to my Navajo students, they thought it was eerie because it sounded like a foreign language except that they could understand it perfectly well.
Please have a look at some of the chapters in The Burgeoning and let us know what you think.