Echolalia is the repetition or echoing of verbal utterances made by another person. Up to 75% of verbal persons with autism exhibit echolalia in some form. There are two types of echolalia: immediate echolalia and delayed echolalia.

The researchers have determined that immediate echolalia often was used with clear evidence of purposeful communication.

Immediate echolalia appears to tap into the person's short-term memory for auditory input. This is defined as the repetition of a word or phrase just spoken by another person.

Immediate echolalia may be used with no intent or purpose or may have a very specific purpose for the individual.

Immediate echolalia may also be used to initiate or maintain interaction or may be used in a noninteractive manner. Knowing the person very well would appear to be the key to understanding their specific use of immediate echolalia.

Delayed echolalia has been defined as the "echoing of a phrase after some delay or lapse of time". Persons with autism who repeat TV commercials, favorite movie scripts, or parental reprimands come to mind when describing delayed echolalia.

Delayed echolalia appears to tap into long-term auditory memory, and for this reason, may be a different phenomenon from immediate echolalia. Because it can involve the recitation of entire scripts, delayed echolalia, is often thought to denote evidence of near-genius intellect.

There are two described categories of delayed echolalia: noncommunicative repetition and communicative repetition.

Delayed echolalia may be interactive or noninteractive and may be used with no intent or purpose or may have a very specific purpose for the individual.