This is probably one of the most interesting areas with a child with Autism. People who have children who do not have any speech might be envious of echolalia. On the other hand I know many parents who have children that drive them wild with the constant repetition. There are some techniques that reduce it.
My child did have echolalia about certain subjects. I thought the repetitive speech helped stimulate more speech. I have run into several parents who report the same experience. So echolalia might be good for some children with Autism.
One family I know found triggers. They then made sure not to talk about the things that triggered the repetitive speech. Unfortunately the family’s friends might trigger the child with Autism. This was helped some by warning friends ahead but never completely.
Of course parents who have a child with Autism know that sometimes echolalia starts without any seeming provocation what so ever. In this case sometimes different sensory techniques have helped reduce tension and stress. Even when it appears there was no reason for stress.
Finally other parents have found it beneficial to remove themselves from the situation. The repetitive speech did not bother their child. It was easier to just go another room or another part of the house at least temporarily.