Table 1.

Communicatively functional models of echolalia.

Study	Participants (n = )	Communicative functions	Notes/Comments
Wolff and Chess (1965)	14 participants 12 x males 2 x females Aged under 8 years	Delayed Communicative repetitions Requests Multiple functions refusing items, objecting to action or activity, indicate a need or desire, and direct others to do something Commentary Used to provide information/comment on current situation	Represented the first study to note that delayed repetitions could serve a communicative function.
Dyer and Hadden (1981)	(No participants)	Delayed Echolalia Negativistic Blocks intrusion of others in their space Time-lag Multiple functions: refusing items, objecting to action or activity, indicate a need or desire, and direct others to do something Transferred Invites/interests the listener into a conversation Mitigated Invites/interests the listener into a conversation	A total of 6 possible functional categories were described in a continuum style. That is, the 4 categories included in this table represent the most communicatively functional echoes. The remaining 2 (stereotypic and egocentric) were believed to serve possible cognitive and self-regulatory purposes. Transferred and mitigated appeared to serve the same function. However, mitigated echolalia is characterised by modifications to the original utterances.
Prizant and Duchan (1981)	4 x males Aged 4:8, 5:2, 6:3, 9:3	Immediate Echolalia Turn taking Used to maintain a social dialogue Declarative Labelling an object or item Yes-answer Agreeance to prior utterance Request Used to request an object	A total of 7 possible functional categories were advanced in the model, however only 4 of these were deemed to serve a communicative function, as seen in the column to the left. The remaining 3 (non-focused, rehearsal and self-regulatory) categories possibly served a cognitive function.
Prizant and Rydell (1984)	3 x males Aged 4:8, 12:4, 14:2	Delayed Echolalia Turn taking Used similar to normal conversational ‘to-and-fro’ Verbal completion Response to verbal routine Label (interactive) Used to label an action or object Providing information Provides new information to listener Calling Gains attention of others to oneself Affirmation Agreeance to prior utterance Request Used to request an object Protest Used as objection to other's actions Directive Used to order other's actions	A total of 14 possible functional categories were advanced in the model, however only 9 of these were deemed to serve a communicative function, as seen in the column to the left. The remaining 5 (non-focused, situation association, rehearsal, self-directive and label (non-interactive)) categories possibly served a cognitive function.
Sterponi and Shankey (2014)	1 x male Aged 5:10	Immediate Echolalia After correction Used to correct prior mistake After directive Used to clarify instruction Delayed Echolalia Other echoes Used as a way to express an opinion Impersonal echoes Used to direct own behaviour	A 6-category model was advanced, with other non-communicative immediate repetitions possibly serving a function only known to the child, termed unusual echoes.
Marom et al. (2018)	3 participants 2 x male 1 x female Aged: 5:2m, 6:6m, 5:8f	Echoing to express strong emotional content Used to express state of emotion Initiate or maintain communication Used as a way to start or continue a social dialogue exchange	This study did not separate echoes pertaining to time (i.e., immediate or delayed). As such communicative echoes were heard as both immediate and delayed repetitions. Model was a total of 6-categories, serving a variety of social-emotional, learning and communicative functions.

Age – respectively (years:months).