Signs of Autism:

T-rex arms: walking around with arms at 90 degrees, sort of like they're stuck after completing a task with them at this angle

Wearing earplugs or headphones: blocks out sound for those who are sensitive to loud noises, possibly true for some individuals with ADHD as well

Hand flapping: sometimes accompanied by jumping

Lining things up (ex. toys): lining toys up in a row or organizing them instead of actually playing with them is a pretty common sign of autism

Russell's sign, a persistent cut or scar on the knuckles, indicates bulimia nervosa. 

If someone uses the word "bubbler" instead of "water fountain" or "drinking fountain", they are likely from Milwaukee or at least Wisconsin. I say this as a Wisconsinite who knows that many people outside of the state have not heard this way of referring to a water fountain. "Water fountain" and "drinking fountain" also have regional differences, but they both have widespread use across the United States, so this wouldn't clue you into much. I've heard that Eastern Massachusetts also uses this terminology, but I have not been there so I cannot say from personal experience.

Source: https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.reddit.com%2Fr%2FMapPorn%2Fcomments%2F9010e8%2Fwhat_do_you_call_that_thing_you_drink_water_from%2F&psig=AOvVaw29qVjSsJfLC6V_DU-fBKgg&ust=1720464567162000&source=images&cd=vfe&opi=89978449&ved=0CBEQjRxqFwoTCMjw0IzMlYcDFQAAAAAdAAAAABAE

Along the same lines, if someone refers to a casserole as a "hot dish" (and especially if they have strong feelings about which term is correct) they are likely from Minnesota or North Dakota.