Inclusion Criteria:  Inclusion criteria:  Meeting study criteria for ASD based on: Autism Diagnostic Observation Schedule(ADOS) criteria for mild-to-moderate concern or greater (for children between 18 and 30 months) or algorithm cut-offs for ASD or autism (31-33 months), Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5)( criteria for ASD) ASD diagnosis by clinician (clinical best estimate) by study team clinical research experts Nonverbal developmental quotient (DQ) of > 63 based on the Visual Reception and Fine Motor subscales Gestational age of 36-42 weeks; Birth weight of > 2,500 grams; Absence of identifiable neurological (e.g., epilepsy), genetic (e.g., Down syndrome, fragile X, tuberose sclerosis, neurofibromatosis) or severe sensory-motor (e.g., cerebral palsy) conditions. Able to walk independently. Children must produce at least three different types of intentional directed (with eye contact or pairing vocalization and gesture) nonverbal or verbal communicative acts per day, with clear and specific examples, per parent report in the Eligibility Interview. Caregiver must conduct symptom screening prior to each research visit Caregiver much wear a mask during visits  Exclusion Criteria:  Having a primary language other than English Family lives >30 miles from a KKI-Center for Autism and Related Disorders(CARD) site (Baltimore; Odenton). Receiving >15 hours of treatment per week at enrollment Child lives in foster care. Caregiver refusing to wear a mask during visits