Pivotal Response Treatment for Individuals With Intellectual Disabilities

Inclusion Criteria for Individuals with Intellectual Disabilities: * Participants will have an age range between 2 and 17.11 years of age inclusive * Male or female * Diagnosis of an intellectual disability based on the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10), and an expert clinical evaluation * have historical evidence of significant abnormal developmental milestones as determined by neurological history * care provider that will reliably bring subject to study visits, and is trustworthy to provide accurate accounts of services provided to the subject Inclusion Criteria for Individuals with Speech Delay/Language Disorder: * Participants will have an age range between 2 and 17.11 years of age inclusive * Male or female * Diagnosis of a speech delay based on the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10), and an expert clinical evaluation * Preschool Language scale (PLS) score of at least 1 standard deviations below age level (for children in the age range of 2-6.11) * care provider that will reliably bring subject to study visits, and is trustworthy to provide accurate accounts of services provided to the subject Exclusion Criteria: * medically unstable (such as having unstable seizures) * primary diagnosis of Autism Spectrum Disorder (ASD) is exclusionary as determined by the investigators