Living with autistic people means making conscious choices about what to say and what not to say.
My son takes everything literally, so when someone askes me when I like another cup of coffee he should serve me just one and not two, because that might upset my son. (Unless he askes again if I want one.)
Sometimes I forget my plans to be aware of what I say.
It's very nice to welcome people downstairs in the morning with an enthousiastic: good morning!
The girls enjoy it. The whole world enjoyes it, but he doesn't react with "a good morning to you too."
He often says: "I don't know if it's a nice day, I'm jst downstairs and haven't had a look outside." or "How can you say it's a good morning. The rain ours down and internet is slow."
When the girls are at home we sometimes have a good laugh about his reaction.
Sometimes his arrival in the morning is more of a theatre act than real life.
"Did you have a good night?"
"How can I tell? I was asleep."
Some people think living like this is a burden. But it's not.
It makes one aware of the content and intention of language. Knowing that language can have many meanings has helped them at school when learning other languages.
So: good morning to you.
Or at least I hope so... :)