The focus of this investigation is to compare the effectiveness of the AAC Generative Language Intervention approach to an AAC Standard of Care condition on preschool sentence productions. All children will use existing AAC iPad applications.

The central hypothesis is that preschoolers receiving AAC Generative Language Intervention will create longer, more grammatically complete sentences compared with the Standard of Care condition. Specific Aim 1 compares these interventions for preschoolers with severe speech impairments and typical receptive language, and Specific Aim 2 does the same for children with Down syndrome. Specific Aim 3 tests for possible moderation of the intervention effect by age, dynamic assessment scores, sentence type, receptive language abilities, prior AAC use, sex, mental age, and disability. Aims 1 and 2 will be accomplished using randomized controlled trials.

Inclusion Criteria:

• Clinical Identification of Significant Speech Impairment
• Must Speak English as a Primary Language
• Must Be Able to Express At Least 25 Words (using any communication mode)
• Must Be Able to Accurately Select Picture Symbols on iPad Communication App with at Least 50% Accuracy
• Vision and Hearing within Functional Limits or Corrected to be within Functional Limits for Study Activities

Exclusion Criteria:

• Clinical Diagnosis of Autism or Social Communication Disorder
• Primary Language Spoken is a Language Other than English