[Max Goodman]

Thanks, RogerBob. It absolutely is melisma (a new word for me--thanks). (On "softly" and "was," though not "creeping" or "sleeping.") But doesn't that strengthen the mismatch of the two patterns? That those syllables get multiple notes each is among the reasons (along with the specific notes and their lengths and maybe other factors I'm too musically unsophisticated to note) that they get more stress than the syllables around them, contradicting the stress pattern of the words.

Or are you saying that to your ear the melisma makes the stress pattern of the music match that of the words?

I suppose the melisma makes the mismatch less noticeable, arguing against the likelihood that Simon wanted the song to sound strange. And I take it that for there isn't much strangeness to the sound.