This plant is toxic to cats FYI whatever its ID. It is a lily of some sort. Lilies are all toxic to cats and dogs. You would think cats know better but some cats are actually attracted to these plants. Dogs as well.
My guess is some hybrid of Hosta. Is this a native plant? In the photo it looks very healthy and well watered (or lots of rain)... I see no signs of rabbit or bug chewing damage, so my guess is it is not growing wild in your back yard. Where are you?
It looks like ginger to me but flowering will help in ID'ing. Best guess, Shell Ginger.