A Relationship Between Early Language Skills and Adult Autistic-Like Traits: Evidence from a Longitudinal Population-Based Study.

The team tracked 8,000 typical toddlers born in 1991-92. They counted how many words each child said at age 2. Eighteen years later they gave the same people an adult autism-trait survey.

They asked questions like “I prefer to do things alone” and “I notice small sounds.” Then they looked for a link between tiny toddler vocabularies and high adult scores.

Kids who knew fewer words at age 2 scored slightly higher on autistic traits at age 20. The effect was small: moving from 100 to 75 words predicted only a 2-point bump on a 50-point scale.

Language mattered more than gender, mom’s education, or social class.

Thurm et al. (2007) saw the same pattern inside autism. Toddlers with ASD who had low joint-attention and few words at 2 were most likely to stay non-verbal at 5. Rebecca’s team now shows the link still shows up—even when no diagnosis is ever given.

Day et al. (2021) looked at adults and found the opposite trend: autistic traits drop as people age. Rebecca’s data say early language still predicts where you start on that downward slope. The two studies fit: poor early vocabulary nudges you higher at 20, but the glide-path down continues.

Han et al. (2025) pooled 25 ABA studies and found high-intensity programs raise language scores. Rebecca’s paper reminds us that even small early gaps matter years later, so starting language-rich ABA early makes sense.

You can spot risk in ordinary toddlers by simply counting words at the 24-month check-up. If a child is on the low side, weave more language models, echoic trials, and mand training into everyday play. You are not treating autism—you are giving extra language practice that may soften later social-communication style.