1) I like the idea of yes/no question tagging. We could use "yes" and/or "no" for tags, or we could have a different question tag altogether. I guess we have "vi" (or something related, if that's verb negation only) as a potential word for "no", but do we have a word for yes?
2) What about other kinds of questions? Would anyone like to tackle question words? Who, what, when, where, how, why, which... and maybe how much/many, which type of, etc.