The robustness of speech-like vocalization in typically developing infants and infants with autism.
Male infants who start chatty but then babble less may need an autism screen right away.
01Research in Context
What this study did
The team watched 113 babies once a month from months.
They counted every speech-like sound the babies made during 10-minute play sessions.
Half the babies were typically developing. The rest either had autism or general developmental delay.
What they found
All babies started strong. Every child made 4-5 speech sounds each minute.
Only the boys with autism or delay lost steam. Their vocal rate dropped over time.
Typical boys stayed steady. Girls showed no clear pattern either way.
How this fits with other research
Brignell et al. (2024) followed verbal kids to age 11. They found early language level, not diagnosis, shaped later growth. Kimbrough adds the first-year vocal dip that sets the stage.
Lyall et al. (2014) saw school-age kids with autism gesture less than peers. Yet more gestures linked to bigger vocabularies only in autism. The two studies seem opposite, but they look at different ages and skills. Together they say: watch both early sounds and later gestures.
Spanoudis et al. (2011) ran an 8-month toddler program. One third of the kids with autism moved into the typical range. Their big gains show the vocal drop Kimbrough found is not fixed. Early help can turn it around.
Why it matters
If you serve baby brothers of diagnosed children, count their babbles each visit. A falling trend is a red flag months before formal testing. Pair this check with later gesture counts and quick-start ABA to keep language on track.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add a 2-minute babble count to your intake for any baby brother of a child with ASD.
02At a glance
03Original abstract
BACKGROUND: Human infants produce speech-like vocalizations ("volubility") at very high rates, 4-5 per minute during waking hours across the first year, far exceeding rates of our ape relatives. AIMS: We document volubility in 127 typically developing (TD) infants, 44 with autism (ASD), and 21 with non-autism developmental delay (DD) through longitudinal recordings and human coding. METHODS AND PROCEDURES: Families of 302 infants (110 not yet diagnosed or with other diagnoses) supplied 8.6 all-day recordings across the first year. Trained coders analyzed 21 randomly-selected 5-minute segments per recording, counting speech-like vocalizations, cries, and laughter. OUTCOMES AND RESULTS: Infants in all groups (including those with other diagnoses or not yet diagnosed) showed volubility of 4-5 per minute for the first year, but boys showed higher volubility than girls in the TD, ASD, and DD groups. While volubility was relatively stable across the first year for both boy and girl TD infants, volubility fell in both ASD and DD boys, while being more stable for girls. CONCLUSIONS AND IMPLICATIONS: Strong similarities in volubility were seen across all groups, but male infants diagnosed with ASD or DD showed falling volubility across the first year, a pattern not seen in TD infants.
Research in developmental disabilities, 2025 · doi:10.1101/2024.01.17.576142