Kanzenshuu

What about the Z Sword/Zeta Sword? Was it called the Zetto sword in the Japanese version (Actually, thinking back to my old fansubs, I think it was)? Then what's the reason for Viz's "Zeta"?

Some kid told me that Tenshinhan becomes second strongest...

I'm just wondering, who taught Goku the fusion technigue? I know that he learned it while he was dead and I could have sworn he mentioned it around the time he was teaching Goten and Trunks how to fuse. Sorry if this is a stupid question...