Children with fragile X syndrome (FXS), the most common known inherited cause of intellectual disability, typically experience communication difficulties. Children with other intellectual disabilities such as Down syndrome also experience communication difficulties. Further, many boys with FXS (some estimates are as high as 35 percent) also are diagnosed with autism. Professionals who work with children with language impairments need to tailor language interventions. But what if language difficulties in children with FXS have a different cause than language challenges in children with Down syndrome or autism? Is having an intellectual disability or autism the root cause of the communication challenges in a child with FXS or does having FXS present a unique set of challenges? New research is beginning to answer these questions. Recent articles by FPG researchers in several journals explore different facets of communication in boys with FXS, boys with FXS and autism, boys with Down syndrome, and boys developing typically. These studies focused on boys because communication and other aspects of development are more severely affected in boys with FXS than girls. The findings will allow professionals to focus interventions efforts to best help children communicate effectively. This document summarizes the findings to date. (A list of resources is included.)