Background  Echolalia is a verbal disorder, defined as ‘a meaningless repetition of the words of others’. It is pathological, automatic and non‐intentional behaviour, often observed in a variety of neurological and psychiatric disorders and above all in autism. We assume that echolalia is an imitative behaviour that is due to difficulties in inhibiting automatic repetition as seen in patients with frontal lobe damage. Our aim is to study the occurrence of echolalia under experimental conditions to investigate the nature of the phenomenon and its relationship with the severity of autism.Methods  Eighteen participants with autism from 17 to 36 years old were recruited; they were administrated the Vineland scale, the Observational Rating Scale of Basic Functions and the Echolalia Questionnaire. In the Echolalia Questionnaire, questions were directly addressed to the autistic subject (induced procedure) or to the subject's caregiver while the subject was free to do what he wanted (incidental procedure). The data were analysed by multivariate regressions and Pearson's correlations.Results  The results showed that echolalia occurred in both experimental situations; the mean value was significantly higher in the induced procedure, but results did not support the correlation with Vineland's score in the incidental procedure. It is likely that the two situations activated different processes. In particular, echolalia was statistically higher in the induced procedure as compared with the incidental one only for subjects with low score on Vineland, but in the incidental procedure, the presence of echolalia appeared to be uninfluenced by the functional capacity of subjects.Conclusions  The two experimental conditions require different monitoring systems to control this verbal behaviour. The echolalic phenomenon is an expression of dependence on the environment and may occur in a situation in which the autistic person is participating in a communicative act and, lacking inhibitory control, repeats the other's communication rather than selecting an answer. The deficit in inhibitory control in this situation does not seem to be present in subjects with higher efficiency. Incidental echolalia reflects the inability of the subject to filter out background environmental noise, which occasionally results in environmental dependency.