From Plutarch's Life of Alciabiades:


“Of all fair things the autumn, too, is fair,”

is by no means universally true. But it happened so with
Alcibiades, amongst few others, by reason of his happy
constitution and natural vigor of body. It is said that his lisping,
when he spoke, became him well, and gave a grace and
persuasiveness to his rapid speech. Aristophanes takes notice of
it in the verses in which he jests at Theorus; “How like a colax
he is,” says Alcibiades, meaning a corax, 1 on which it is
remarked,

Note 1. This fashionable Attic lisp, or slovenly articulation, turned
the sound r into l. Colax, a flatterer; Corax, a crow.

lisp
vi.
5ME lyspen, earlier wlispen < OE 3wlyspian < wlisp, wlips, a lisping, akin to Ger lispeln, MLowG wlispen, wilspen, of echoic orig.6
1 to substitute the sounds (0) and

My dictionary does not give lisp as change from "r" into "l". Should it?