Jargon takes quite a bit of collective time to establish. Instead of jargon, how about offensive phrases? Since AI lacks both creativity and the ability to be offensive (barring current workarounds/hacks), perhaps an easy way to (temporarily) prove you are human on the internet is to respond with unique, creatively offensive content.

"How are you today, you irradiant sack of sludge?"

"Oh hey douche firehose, can't complain."