You haven't thought this one all the way through... Imagine a user names a folder "Bin", which maps to ID 123, and the internal trash folder maps to ID 7, and the user sees as "Trash", because that's their interface language.
The user now changes their interface language to England, and suddenly they have two "Bin" labels that map to different sets of things. They behave inconsistently and frustrate anyone who gets into that state. Some messages might even be in "Bin" and "Bin" at the same time! Searching for "in:Bin" returns just one set, or the other, or both.
The user now changes their interface language to England, and suddenly they have two "Bin" labels that map to different sets of things. They behave inconsistently and frustrate anyone who gets into that state. Some messages might even be in "Bin" and "Bin" at the same time! Searching for "in:Bin" returns just one set, or the other, or both.
Doesn't really sound like a good solution...