lisp vs defect of speech

lisp and defect of speech both are nouns.

Word	Noun	Adjective	Verb	Adverb
lisp	Yes	No	Yes	No
defect of speech	Yes	No	No	No

As nouns, defect of speech is a hypernym of lisp; that is, defect of speech is a word with a broader meaning than lisp:

lisp: a speech defect that involves pronouncing `s' like voiceless `th' and `z' like voiced `th'
defect of speech: a disorder of oral speech

Other hypernyms of lisp include speech defect, speech disorder.

lisp (noun)	defect of speech (noun)
a speech defect that involves pronouncing `s' like voiceless `th' and `z' like voiced `th'	a disorder of oral speech

lisp (verb)	defect of speech (verb)
speak with a lisp