localization and weaken

Hello, everyone

I am a little confused about the discrimination between softening, weakening and localization.

In my opinion, softening is against hardening, corresponding to the decrease of slope in the hardening curve.

weakening is for what?

Localization is about localized plastic flow. 

localization is a phenomenon that explain the softening, so "localization" can not give help for better simulation result. Is that coreect?

 Thanks for correcting the views above!