Spotlighting two highly prevalent genetically-caused developmental disabilities--Down syndrome and fragile X syndrome--this text clarifies the distinct speech and language issues associated with each disorder and helps readers conduct individualized assessment and intervention. An essential upper-level textbook and an invaluable professional reference, this book gives readers the up-to-date research and clinical insight they need to- understand the behaviors, characteristics, and genetics associated with both disabilities- see how speech and language develop across the life span- tailor assessment and intervention to individual needs and abilities- apply the techniques where appropriate with individuals who have other disabilities, such as autism- encourage family involvement