JRR Tolkien saw the myth-making process at work in his lifetime when he got back, indirectly (via an identification query sent from the USA to Oxford University) an orally-transmitted version of his poem Errantry which had preserved the 13th century word 'sigaldry' (= enchantment).
"...bore out my views on oral tradition (at any rate in early stages): sc. that the 'hard words' are well preserved, and the more common words altered, but the metre is often disturbed."
(Letter to Rayner Unwin, 22 June 1952).
This corresponds to the way in which the garbling process of oral transmission yet retains a fascinating core; based around the preservation of strange words or phrases.
I find this quality in many nursery rhymes - for instance in the counting song 'Green grow the rushes O' which has always cast a spell over me since childhood.
This is the final verse as I knew it:
I'll sing you twelve O
Green grow the rushes O
What are your twelve O?
Twelve for the twelve Apostles
Eleven for the 'leven who went to heaven
And ten for the ten commandments
Nine for the nine bright shiners
And eight for the April Rainers
Seven for the seven stars in the sky
And six for the six proud walkers
Five for the symbols at your door
Ands four for the Gospel makers
Three, three, the rivals
Two, two, the lily-white boys
Clothèd all in green, Yo Ho
One is one and all alone
And evermore shall be so
Rather than regarding this lyric as nonsense, I assumed that it meant something.
Probably it was ('just') a Christian mnemonic (although this never crossed my mind as a child - e.g. I had no idea what was meant by 'Gospel makers') , and certainly it has been brushed-up by revivalists (including re-regularising the metre - because ordinary people have tin ears when it comes to scansion, and fail to make even the simplest and most obvious changes to maintain or restore regular metre).
But after all this explaining-away, there remains an extraordinary sense of a world of mysterious numbers and symbols.
Five for the symbols at your door! Was this (I wondered) about somebody coming to the door of my house - something like carol singers, but showing a symbol?
Robert Graves guessed that this meant the pentangle, or interlaced five pointed star; this is indeed a Christian symbol in Sir Gawain and the Green Knight - although any such tradition has since been lost, and the pentangle is now the premier symbol of neo-pagans.