Fisher and Hughes wrote:

> "Pound clarified melopoeia as dependent
> on 'the actual beat, rhythm, and timbre of [the] words for the emotional
> effect of [the] work.' Because this type of lyric poem was made to be
> 'delivered with varying pitch,' he called it 'cantabile' to distinguish
> it from poems intended to be spoken or half-chanted, and noted that the
> word sounds would be joined quite differently for melopoeia cantabile
> than for all other types of poetry."  [single quotes are from Song by EP]

Anthony Burgess wrote on this at length, in a book on music and writing
which I do not have to hand nor am I near a network to look it up.
Burgess was of course highly accomplished musically and his discussion
of the issue is not lightweight, very practical stuff; if you hadn't
noticed the innate pitch relationships in the English vowel repertoire
you will wonder how you'd missed it after reading Burgess.

I have wondered how lyricists writing in tonal languages fit the shapes
of vowels to the shape of the melody, there must be musical effects
ranging from clever to amazing available to the hands of an expert.

Now, if I were feeling maliciously pedantic or were it closer to the
first of April, I might be tempted to mount an argument that "leading"
is used here in the sense from typography, that is to say the space
between the lines, once achieved by inserting minute amounts of lead
among the fragments of moveable type.  EP after all did do the space
between lines rather well.

--
Cheers, Tim Bray (http://www.tbray.org/ongoing/)