No, I’m not familiar with him, but then, I didn’t start really talking until I was about 5 years old. However that was because English was my second language, and ASL (American Sign Language) was my first language (since my parents were deaf). I was taken out of my home to a relative’s home for about one year to immerse myself in English. It was okay after that.
But “ASL” and the deaf culture have altered my thinking processes since that time.
Sowell, of course, is best known as a prominent black conservative economist. Brilliant mind. He was also a late-talker and has explored that area in some of his work. As far as I know, he doesn’t necessarily focus on Autism as such, but as a general observation he feels that late-talking is not such a bad thing and some people worry about it unnecessarily — if there are no other reasons to believe there is an actual problem. Problems are problems. But late-talking, by itself, is not always a problem.
I took 2 courses in “Language for the Deaf” in college from a woman whose parents were deaf. She had some interesting stories...I assume you do as well. :)