Value-added predictors of expressive and receptive language growth in initially nonverbal preschoolers with autism spectrum disorders.

Leigh et al. (2015) watched 3- to 5-year-old kids with autism who had no words at intake.

They tracked joint attention, gestures, sounds, parent talk, and autism severity for one year.

The team asked: which early signs best forecast later spoken language?

Kids who looked when someone pointed, showed toys on purpose, and heard parents talk back learned the most words.

More different consonants at the start helped expressive growth.

Lower autism severity and early understanding helped receptive growth.

Rose et al. (2020) later added AAC to the story. They found that kids who stared at pictures, played with intent, and learned AAC symbols made big word gains even when IQ was low.

Song et al. (2022) flipped the script. They saw that only baseline word level mattered; joint attention and parent input faded out. Their newer, larger sample updates the 2015 list.

McDaniel (2025) seems to clash. In boys with fragile X, consonant inventory helped, but intentional communication did not. The kids have a different gene, so the clash is more about diagnosis than method.

You can act today. Watch for shared looks, pointing, and showing. When you see them, jump in with clear, simple words. Coach parents to do the same. If the child uses few consonants, add sound play and oral motor games. These cheap, natural moves still sit at the top of the evidence pile, even as newer studies tweak the details.