Article: Response Interruption and Redirection (RIRD) as a Behavior Intervention for Vocal Stereotypy: A Systematic Review. By Spencer and Alkhanji, in Education and Training In Autism and Developmental Disabilities, 2018, 53(1).
You may know that one of the things we look for to diagnose ASD is stereotyped behavior, which is "repetitious behavior that does not serve a clear function for the individual engaging in it." This is different than your child asking, "Are we there yet?" for the 100th time when you are 20 minutes into an 8 hour car trip. That repetitive behavior serves the function of making you angry, and thus entertaining your child, who is bored. Those who have seen stereotyped behavior can quickly point it out. That stereotyped behavior can come in a couple forms, one of which is vocal stereotypy, or the repeating of noises or words.
One interesting thing mentioned in this article is that clinicians believe that stereotyped behavior, and specifically vocal stereotypy can actually get in the way of learning useful, functional behaviors such as those that help children succeed in academics and social interactions. Plus, vocal stereotypys can be obnoxious and disruptive. For all these reasons and more, vocal stereotypys can and should be treated.
That was the whole point of this article. There is an intervention (RIRD, in the title of the reviewed article), which seems to be effective not only in reducing vocal stereotypys, but in some cases, increasing the use of functional vocalizations. Based on the article description, it seems to work well for little kids (let's hear it for early intervention) and is fairly simple to administer. Go ahead and do some research on it online and/or talk to your pediatrician if you are looking for a place to start.