Richard Mellish wrote:

Although John Stickle regarded the fragment that he knew as a bit of nonsense, and the Shetlanders who retained a much more complete version into the 1800s had probably long lost all understanding of the refrains, Child nevertheless printed a plausible reconstruction, with advice from Grundtvig, who surely had some knowledge of older languages related to his native Danish.

Granted, as long as you'll allow that the Child/Grundtvig reconstruction was a reconstruction, not a certainty.

But my (mis-stated) point was your first point, that the informants (and, of course, the collectors) had lost the meaning, and that the refrain as a result was being corrupted.

My point is, Norn is a dead language that never really achieved a fixed or a written form. A few extracts from Glanville Price, editor, Encyclopedia of the Languages of Europe, p. 331 (the entry on Norn): "After [1469], the position of Norn seems to have declined rapidly. By the 17th c., most if not all Orkneymen and Shetlanders were probably bilingual," and Norn went downhill from there.

"Our knowledge of Norn stems chiefly from brief comments in the accounts of travelers or in general descriptions of the Northern Isles.... George Low... not only described the linguistic situation... on the outlying island of Foula during a visit to Shetland in 1774, but appended three specimens of Nron, the Lord's Prayer, a list of some 30 everyday words, and a 35-stanza ballad." That's basically all we have, and it was taken down by someone who did not know Norn. Comparing Low's material with the few other known words, "There thus seems to have been dialectal variation within Shetland. There is also slight evidence of linguistic divergence between Shetland and Orkney."

Thus while the Child/Gruntvig translation probably preserves the meaning, the actual original phonetic text behind the surviving versions cannot be constructed, because of the damage done to the text by oral transmission combined with the fact that we don't know enough about the (lost) source language.

On a side note, the discussion here isn't really of "King Orfeo," but rather of Collinson -- but if one wishes to study "King Orfeo," it's very important to read Emily Lyle's writings on "King Orpheus," published in her essay collection Fairies and Folk. For those who want to dig into the material behind what Lyle wrote, one should also see Rhiannon Purdie, Shorter Scottish Medieval Romances, which includes the surviving fragments of the "King Orpheus" romance. I am not convinced, as Purdie is, that "King Orpheus" (as opposed to "Sir Orfeo") is the ancestor of "King Orfeo," but it's good to look at both texts.