All participants will receive the Social ABCs program, a 6-week parent-mediated intervention. Each week includes one group session delivered via Zoom and one to two individual face-to-face coaching sessions with the parent and child. The program teaches parents strategies to support their child's social communication during everyday routines such as play, meals, and caregiving activities.

The Social ABCs, a parent-mediated intervention for toddlers with suspected or confirmed Autism Spectrum Disorder (ASD), originally developed in Canada (Brian et al., 2016). It is based on principles of Pivotal Response Treatment (PRT, grounded in Applied Behavioural Analysis). The two main goals of the intervention: early functional verbal communication and positive affect sharing in the context of play and caregiving activities.

The current study follows the Group Social ABCs protocol, a 6-week parent-mediated intervention designed to support early social communication in young children with autism. The program is delivered at two research sites: Soroka and Hebrew University of Jerusalem. Each week, parents participate in: One group session via Zoom, led by a trained Social ABCs coach, with 3-5 parents per group. These sessions introduce strategies and provide peer support, and one to two individual face-to-face coach (See #17-745 for more information).

Feasibility will be assessed by tracking recruitment rates, retention throughout the 6-week program, and attendance at both group and individual coaching sessions. Acceptability will be evaluated through parent-reported satisfaction surveys completed at the end of the program, as well as qualitative feedback on the format, content, and delivery of the intervention.

The HCDI is the adapted Hebrew version of the MacArthur Communicative Development Inventory (MCDI). The MCDI is a well normed, reliable, and valid tool for vocabulary assessment (Bates et al., 1994). The HCDI is a reliable and sensitive measure of lexical development and emergent grammar, capturing wide variability among Israeli toddlers (Maital et al., 2000). We utilized two versions of the inventory: Words & Gestures for toddlers up to 25 months and Words & Sentences for children 25 months and older. This questionnaire relies on caregiver report to assess children's receptive and expressive vocabulary, speech comprehension, gesture use, morpheme acquisition, and syntactic complexity. In our study, we focused on two variables: receptive vocabulary total score and expressive vocabulary total score

The PSI-SR is a self-report, 36-item index of parenting-related stress. Each item is scored on a 5-point Likert-type scale, with higher scores indicating greater parenting stress (range 36-180). Alongside a total stress score, the three subscale scores are derived, each composed of 12 items (range 12-60): parental distress (PD), measuring distress caused by the burdens and restrictions of childcare and personal stressors (e.g., depression, conflict with partner); parent-child dysfunctional interaction (PCDI), assessing parents' negative perception of their interactions with the child and the degree to which the child does not meet their expectations; and difficult child (DC), measuring parents' views of the child's self-regulatory functioning. It also includes a defensive responding scale (DR; seven items, range 7-35), which assesses if the parent is trying to deny or minimize problems.

This is a semi-structured, standardized behavioral assessment of social communication abilities and restricted and repetitive behaviors. We used the ADOS-2 calibrated severity scores (CSS) to estimate autism symptom severity while separating CSS into the Social Affect (SA) and the Restricted and Repetitive Behavior (RRB) domains. The CSS were specifically developed to enable comparison of autism severity independent of the child's age and language abilities (Hus et al., 2014).

Verbal ability was evaluated using item A1 of the ADOS-2