Final answer:
Jack's behavior of repeating what is said to him, known as echolalia, is a common characteristic in individuals with autism and signals a need for language development support.
Step-by-step explanation:
The communication pattern where Jack repetitively "plays back" whatever is said to him is known as echolalia. Echolalia is a common trait in individuals with autism spectrum disorder (ASD). It can be immediate, echoing the speaker right away, or delayed, repeating the phrase at a later time.
While echolalia can serve various functions for individuals with ASD, including communication, self-regulation, or engagement in social interaction, it is often a stepping stone in language development. Contrary to a direct response or adapting language for practical use, echolalia indicates a need for further language and social communication support.