We say Autistic person. Not person with autism. The preference is not cosmetic. It is political, and it is specific, and the community has been clear about it for a long time.
Person with autism is person-first language. It was developed for disability contexts in the 1980s with good intentions. The underlying idea was that the person came first, and the condition was secondary, and emphasising the personhood would help counter stigma. For some disability communities, this framing fits. For the Autistic community, it does not.
Person-first vs identity-first
Autism is not something we have. It is something we are. It is not separable from us. It is not a condition carried by an otherwise neurotypical person. It is the shape of the brain we are using to read this sentence. The way we think, perceive, communicate, regulate, love, work, and move through the world is Autistic, and this cannot be detached for the purposes of grammar.
Saying person with autism implies that there is a default person underneath, and the autism is an attachment. There is no such person. If you removed my autism, I would not be myself minus autism. I would be a different person, using a different brain, with a different life. The grammar that implies otherwise is doing work against us.
Why grammar matters here
Identity-first language is a reclamation. It says this is who I am, not what I have. It puts the word Autistic in the same grammatical place as Jewish, or queer, or deaf, or Greek. It is a description of being, not a possession.
Some Autistic individuals do prefer person-first language. Respect the individual. The default, in our community and on our sites, is identity-first, because that is the preference of the majority of us and of most Autistic-led organisations globally.
If you are writing about us
If you are writing about us, please follow our lead on this. It is a small edit. It is also the clearest signal that you have listened to the community rather than to the textbook that was written about us.