How did the Vulgar Latin 'parabola' evolve to mean 'word'?

Question

parable (n.)    mid-13c., parabol, modern form from early 14c., "saying or story in which something is expressed in terms of something else,"
from Old French parable "parable, parabolic style in writing" (13c.),
from Latin parabola "comparison,"
from Greek parabole "a comparison, parable," literally "a throwing beside," hence "a juxtaposition," from para- "alongside" (see para- (1)) + bole "a throwing, casting, beam, ray," related to ballein "to throw" (see ballistics).

Replaced Old English bispell. In Vulgar Latin, parabola took on the meaning "word," hence Italian parlare, French parler "to speak" (see parley (n.)).

To connect word to the syntagma para- + bole, I guessed the sad possibility that an illterate may just recklessly throw or cast words alongside each other. But my guess appears wrong, because parabola had already evolved to mean 'comparison'. My 2nd guess is that words can be used for comparison, but this connection seems too faint. Maybe I erred again.

So would someone please explain? I heed the Etymological Fallacy. But what are some right ways of interpreting the etymology, to make it feel reasonable and intuitive?

Answer 1

There is a parallel double-borrowing from Greek with amphibolum.(my emphasis)

Amphibolia (Cic), amphibolum, id. quod,
Amphibologia ....An ambiguity, an equivocation; when a sentence may be construed two ways citing Terence and Quintillian. (Ainsworth, main thesaurus.)

Classical borrowing from Greek, rhetorical terms.
In late Latin this word is given in Ainsworth 'Voces' dialects, late usage.

Amphibalum =amphibolum a loose garment, enveloping the body from every side Voss.

For the physical meanings of parabola or amphibolum the throwing is physically up/against or around. But in rhetoric it is not so much the words, as the meanings that are thrown up against each other, or entangled with each other.
The Greek rhetorical use is certainly first century.