The purpose of this study was to analyze secondary data collected from a sample of 173 mother-infant dyads comprised of infants at high- and low-risk for autism spectrum disorder (ASD) at 12 and 36 months of age. More specifically, the study assessed the predictive capacity of a cumulative risk index (CRI) of several maternal and child factors; risk is defined by eight factors: 1) infant sex, 2) receptive language, 3) expressive language, 4) autism symptomology, 4) social-communication, 5) gesture, 6) maternal depressive symptoms, and 7) maternal concerns for ASD, and their singular and cumulative predictive impact—moderated by group assignment—on later child language scores on the Mullen Scales of Early Learning (Mullen, 1995). Thirty-six children received a diagnosis of ASD, 31 of whom were at high-risk at 12 months. Risk at 12 months was predictive of receptive and expressive language at 36 months and resulted in increased likelihood of an ASD diagnosis at 36 months. The CRI, 12-month receptive language, and maternal concerns were significant, unique predictors of expressive language at 36 months. As well, the CRI, 12-month receptive language, and gesture were significant, unique predictors for likelihood of ASD diagnosis at 36 months. Children at high-risk for ASD displayed increased cumulative risk in early developmental domains compared to children at low-risk that may index prospective language outcomes. The implications of these findings and the burgeoning research in high-risk for ASD are discussed.