echolalia vs echo

echolalia and echo both are nouns.

Word	Noun	Adjective	Verb	Adverb
echolalia	Yes	No	No	No
echo	Yes	No	Yes	No

As nouns, echo is a hypernym of echolalia; that is, echo is a word with a broader meaning than echolalia:

echolalia (noun)	echo (noun)
(psychiatry) mechanical and meaningless repetition of the words of another person (as in schizophrenia)	an imitation or repetition
an infant's repetition of sounds uttered by others	the repetition of a sound resulting from reflection of the sound waves
	a reflected television or radio or radar beam
	a close parallel of a feeling, idea, style, etc.
	a reply that repeats what has just been said