lallation vs speech defect

lallation and speech defect both are nouns.

Word	Noun	Adjective	Verb	Adverb
lallation	Yes	No	No	No
speech defect	Yes	No	No	No

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

lallation: defective articulation of the `l' phoneme or the phoneme `r' is pronounced as `l'
speech defect: a disorder of oral speech

Other hypernyms of lallation include defect of speech, speech disorder.

lallation (noun)	speech defect (noun)
gibberish resembling the sounds of a baby	a disorder of oral speech
defective articulation of the `l' phoneme or the phoneme `r' is pronounced as `l'