Autism & Developmental

Vocalizations of minimally verbal children with autism spectrum disorder across the school year.

Bak et al. (2019) · Autism : the international journal of research and practice 2019
★ The Verdict

Minimally verbal school-aged children with autism will not start talking on their own—you need to add contingent echoing or parent coaching right away.

✓ Read this if BCBAs working with minimally verbal school-aged students in public or private school settings.
✗ Skip if Clinicians serving highly verbal teens or adults.

01Research in Context

01

What this study did

The team followed nine minimally verbal school-aged children with autism for one full school year.

They used small recorders to count each child’s vocal sounds and adult interactions every day.

No language therapy was added; they just watched what happened on its own.

02

What they found

Eight of the nine children made no more sounds at the end of the year than at the start.

Talk with adults stayed near zero for all nine kids.

In short, without help, their voices did not grow.

03

How this fits with other research

Crysdale et al. (2026) show a quick fix: when adults echo a preschooler’s sounds during play, the child soon doubles their vocalizations.

Bao et al. (2017) found the same boost in toddlers when parents learned the Social ABCs script.

These gains clash with Savana’s flat line, but the difference is age and method: the younger kids got active coaching, while Savana’s group got none.

Fusar-Poli et al. (2017) tracked adults with autism plus ID for ten years and also saw no real skill change, backing the idea that without targeted teaching, progress stalls across the lifespan.

04

Why it matters

If you serve minimally verbal school-aged clients, do not wait for speech to appear on its own. Use brief, adult-delivered tactics like contingent vocal imitation or parent scripts early and often. Check for echoic prerequisites first—mands, vocal play, motor imitation—and teach those if missing. Without this push, a year can pass with zero new words.

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Pick one student, echo any sound they make within one second during play, and tally if their vocalizations rise across the week.

02At a glance

Intervention
not applicable
Design
case series
Sample size
9
Population
autism spectrum disorder
Finding
null

03Original abstract

Little is known about the language trajectories of minimally verbal school-aged children with autism spectrum disorders. The present investigation conducted observations across two elementary schools over an entire school year to analyze the vocal language development of nine minimally verbal children with autism spectrum disorder between the ages of 6 and 10 years, and their educational service providers. A Language Environment Analysis™ device automatically recorded and disaggregated over 743 h of data on child vocalizations, and vocal interactions with adults. Vocalizations did not increase for eight of the nine participants, and conversational counts between participants and adults were near zero across the entire year. These results speak to the need for additional research examining language development and potential intervention strategies among minimally verbal children with autism spectrum disorder.

Autism : the international journal of research and practice, 2019 · doi:10.1177/1362361317747576