intransitive verb

1. to substitute the sounds (t̸h) and (t̸h) for the sounds of s and z, as in pronouncing sing as though it were thing
2. to speak imperfectly or like a child

Etymology: ME lyspen, earlier wlispen < OE -wlyspian < wlisp, wlips, a lisping, akin to Ger lispeln, MLowG wlispen, wilspen, of echoic orig.

transitive verb

noun

1. the act or speech defect of lisping
2. the sound of lisping