https://www.lifeprint.com/asl101/fingerspelling/fingerspelli...
https://www.lifeprint.com/asl101/fingerspelling/fingerspelli...
Here's a fun example. ASL allows, maybe even requires, negation after the statement. An interpreter friend of mine was interpreting Wayne's World in a mixed crowd. The whole "<statement>... NOT!" joke gets laughs from the hearing audience and the Deaf audience doesn't understand why.
However, ASL also makes much, much heavier use of rhetorical questions than English does. You might even introduce yourself with "MY NAME WHAT? [NAME]" (i.e., "What is my name? [Name]"). So perhaps it would just look like you're doing that.
(Disclaimer: I don't know ASL. I know some Irish Sign Language, which is related, but dropped out before completing my interpreter training. I have a bit of a fascination with sign language linguistics, but I'm no expert.)
For example, it would be like me saying, "'h', 'e', 'l', 'l', 'o'" instead of whatever translated 'hello' in ASL.
Native ASL speakers who are completely illiterate in english certainly exist, and I'm not sure at all if they know or use finger spelling.