Changing Item Name with Lang

I want to rename all stone tools into copper tools. It's my first time doing this..
Can I just place the items I want into the lang file, and it'll just mix it with the vanilla game? Or do I have to copy and paste ALL of the translation keys?
If it's the 2nd, does this mean any texture pack that also wants to change an item name will have to overwrite my name changes with the default? (As in turning the copper tools back into stone)