205. What 707 Autistic Preschoolers Reveal About Who Develops Speech—and Who Doesn’t

If you work with preschoolers with autism and you care about spoken language outcomes, this episode matters. A lot.

In today’s episode of The Preschool SLP Podcast, we unpack the largest study to date examining why some autistic children do not develop spoken language, even after receiving high-quality, evidence-based early intervention.

The takeaway is blunt:
 Motor imitation doesn’t matter a little. It matters a lot.

Inside this episode, we cover:

• Why one-third of autistic preschoolers in a large, multi-site study did not advance in spoken language despite receiving ~10 hours/week of evidence-based intervention
• How motor imitation emerged as a key distinguishing factor between children who advanced in speech and those who did not
• What neuroscience tells us about mirror neurons, empathy, perspective-taking, and speech development
• Why speech develops from the inside out: core → proximal → distal → speech. And, what happens when we skip the body and go straight to the mouth
• How motor imitation supports:
  • Entry into peer play
  • Social communication
  • Speech motor planning and execution
  • Prefrontal–cerebellar connectivity
  • Why this research gives us a “crystal ball”—not to maintain the status quo, but to do something different earlier
  •  You can’t build speech on a system that can’t yet support posture, movement, imitation, and motor planning.
  • If motor imitation is weak, speech outcomes are at risk, pretending otherwise doesn’t help children.

Clinical bottom line:

If a child presents with:

• Severe autism presentation
• Limited or absent spoken language
• Poor motor imitation

Then motor imitation must be intentionally built into intervention, alongside AAC, multimodal cueing, movement-based learning, and robust communication supports.

This episode challenges us to stop treating mouths—and start treating children.

🎧 Want practical ways to integrate motor imitation, movement, AAC, and literacy?

Join the SIS Membership for ready-to-use, movement-based, evidence-informed activities designed for real preschoolers in real settings:
 👉 https://www.kellyvess.com/sis

Vivanti, G.L, et al. (2025). Proportion and profile of autistic children not acquiring spoken language despite receiving evidence-based early interventions. Journal of Clinical Child & Adolescent Psychology. https://doi.org/10.1080/15374416.2025.2579286