Neologisms and idiosyncratic language in autistic speakers.

The team listened to speech samples from autistic children, kids with intellectual disability, and neurotypical peers.

They counted made-up words and odd phrases that only the speaker seemed to understand.

No one tried to teach or fix anything; they just recorded what each child said.

Autistic children used more made-up words and odd phrases than the other two groups.

These quirky words did not link to one single cause like low IQ or poor social skill.

The stranger words often popped up when the child tried to talk about harder ideas.

Tsao et al. (2003) saw a similar pattern: autistic kids skip typical word errors like under-extension and lean on object parts to name things.

Geelhand et al. (2025) later showed the odd style lasts into adulthood; autistic adults talk more only when paired with non-autistic partners.

Sutherland et al. (2017) seems to clash at first: they proved autistic kids can learn new words. The key difference is J et al. watched free speech while Rebecca et al. taught words on purpose.

Expect novel words during play or conversation, especially when the topic gets tricky. Do not mark every odd word as wrong; instead note the context and gently offer a clear label. If you need to teach new vocabulary, use both rich context and direct definitions, because the 2017 study shows both help. Finally, watch partner mix: mixed-neurotype pairs may need extra time for shared meaning.

A neologism is an invented word or a novel word form that a speaker uses in place of a conventional term. Idiosyncratic language refers to using real words in personal or unusual ways whose meaning is clear mainly to the speaker.

Both are descriptive features of expressive language, not diagnoses in themselves. They are noted here because their pattern differs in autistic speakers compared with matched peers.

Volden and Lord coded language samples from matched groups of autistic, intellectually disabled, and typically developing children. More autistic children used neologisms and idiosyncratic language than the control groups, and no single cognitive, social, or linguistic factor fully explained the difference.

Autistic speakers were more likely to substitute words that had no phonological or semantic link to the intended word. Notably, for the autistic groups the frequency of idiosyncratic language increased as language complexity rose, the opposite of the decrease seen with growing skill in the comparison group.