From R. Vaughan Williams,
The White Gates.
Westcott Road,
Dorking.

Sept 15 [early 1950s]

Dear Father George
I return the essay with many thanks.¹ It has been interesting me much and taught me a lot – But there are two points you seem to ignore.
(1) The ‘tropes’, as I understand were words added to the melismata which gradually  grew on to the plainsong – I was always taught that these melismata were vocal flourishes added to the plainsong by coloratura singers in  the chancel to show off their skills – and that the addition of the words was an attempt to purify the chapel music of meaningless flourishes which grew up owing to the vanity of singers like the vocal cadences of 18^th century opera. – I seem to remember that the musical reforms which led to Palestrina insisted on syllabic settings and deprecated melismata as being more “showing off” and not conducive to piety & reverence.
(2) We must recognize the fact that English Folksong, as we know it now is practically syllabic – Sharp² used to hold that the few melismata which there were were additions by concert singers (see & compare the “sheep shearing song” in F.S. from Somerset³ with  “Sweet nightingale” in English Country Songs where there is a melisma, at the cadence, which is syllabic in the “sheep shearing” & Sharp, if I remember, held that the melismatic version was a perversion by a professional singer). – I can at the moment think of only two melismata in English Folksong (1) “My Bonny Boy” (English Country Songs) (every beautiful one) and “John Barley Corn” where the melisma is set to nonsense syllables “gee no” etc.
If we look at the mediaeval German Folksongs (solo songs) which were converted into chorals for the people we always find the final melisma cut out or made syllabic (e.g. “Innsbruck” in its original form and as it was sung in the time of Bach). Does this square with the theory that the melisma is a natural form & expression with the folk singers?
Yours sincerely
R Vaughan Williams