I hope some people submit talks about formal languages or type checkers or kinds of formal logic systems or how to think of types as something which isn’t sets.
I was considering sending a proposal to present FreeSpec, but I couldn’t find what guidelines these proposals shall comply with :\.
Aren’t the guidelines nicely described in the linked page? Topics and formats are there. There’s also a LambdaConf chatroom and proposal review group on the FP slack, if you’d like to ask questions there.