Autistic son swearing!

[Whowhatwherewhen01]

My 4yr old ASD/ADHD son keeps repeating a swear word he overheard. It doesn’t matter how many times I tell him we don’t use those words, ignore it when he does it, enforce a time out, his impulse control is so nonexistent he just blurts it out all the time.
He’s starting school this year. He’s got
a diagnosis and an EHCP so school are aware of his condition but I’m worried what they will do if he is swearing in the classroom.

Meet with the school and agree between you all how it will be dealt with. I teach in secondary and we have students who have outbursts, tics etc. and it will be on their individual plan how to deal with these moments. It's better that the school go into this prepared.

My NT daughter heard a little boy at preschool saying a “rude” phrase and getting a response to it - and since then she has been saying it on repeat over the past few days/week.
I think any response reinforces it (anger/shock/ laughter) which leads to it happening more, it’s like they are getting a response to a communication. Also autistic kids sometimes like to repeat the same phrases for a number of reasons (they like the familiarity/the sound of it/ curious about the response).
So I think what I would do is try to respond to it like it is any other word and respond in a more lively way to other more appropriate phrases he is using. Then when he is ready (and this may not be for a long while, even years depending on where he’s at developmentally at the moment) you can talk about what is an appropriate and inappropriate thing to say.
What I find with my autistic child is that there are difficult phases (eg. hitting other kids) and I would panic and think he’s going to be doing this when he starts school/ when he’s an adult and then I would respond in a way which actually didn’t help him to find other ways of expressing himself. Then the phase would naturally pass by itself (and another one would come). Also any supportive teacher who understands neurodiversity will get this and help you find a way to manage this if he is doing it at school.
So easier said than done, but try not to worry, they never cease to surprise us!

Can you get him to change to another word?

I found ignoring ineffective with my autistic son. He needs to be told explicitly. Ignoring is a hint really, an NT-friendly non-verbal communication that is not a good choice if I want the message to get through. He was just mystified by my apparent sudden deafness. No lessons were learned.

Maybe something like a hand signal could help, a specific sign for "wrong word", distinct from a general "be quiet". Clear but not fun or interesting. I would focus on trying to get the message across rather than punishing, unless you are pretty sure he is doing it with intent to disrupt (which seems unlikely in an autistic 4 year old.)

Definitely agree a process with his teacher. They may have some good ideas. Substituting or extending the word to make it less rude is also a good idea. Maybe come up with a shortlist of alternatives and see if he likes one of those instead. It's finding something that taps the same buttons in his brain, it might not be one that sounds that similar to you. Or are there other non-swear words he already repeats, that you could feed back to him as a sub?

I agree about being explicit. My DD is autistic and has a learning disability, we just tell her that the word is not a good word, she's not in trouble or anything, we just have to tell her explicitly. Ignoring something relies on the other person picking up on that as a social cue.