I've read that there are enzymes in human saliva which will break down starches, so ancient peoples chewed rice, corn, or somethin' and then spit it out and then fermented it. Has anyone tried this?

I have heard of this, but with malted barley and commercial enzymes why bother? I know someone who tried it on a small scale; what a waste of time. You would need an entire village chewing and spitting to get anywhere! Villages are typically realted somehow so they may put up with this disgusting mess. I wouldn't! If you can't get anything else buy some Beano and don't drool in the mash.

If you really want to swap saliva with somebody then why not distill a nice fruit schnapps and ply your wife or girl friend with it. The results will be far better pleasing then what you are thinking about.

It took some time but I got the guy to tell me the final results. It was not that good. Yes it fermented but it smelled off and tasted awful.

You must be preparing for some very primitive conditions if you want to use saliva. Even prisoners don't use saliva. They get raisins or use bread for yeast and make mixed fruit wine with orange juice. The important thing is to make the mash acidic to prevent unwanted bacteria.