The only folder in IMAP that has a standardized name is INBOX. So in order for folder name localization to work across multiple clients there has to be a way to attach a semantics label like "Junk", "Drafts", or "Trash" so clients can discover which folder is which. The standard way to do this is specified in RFC 6154. Unfortunately our IMAP server does not support RFC 6154 at present; you might want to put in a request for that. (Of course the server supporting RFC 6154 won't make clients support it; you'll have to check the various clients you're interested in to see if they do.)
To add to Ned's response, most IMAP clients will allow you to configure localized "Junk", "Drafts" and "Trash" folders, but it usually involves local client configuration or site client configuration and you'll have to do it the same on each client used by a given end-user to get things working well. RFC 6154 is the standard way to coordinate multiple clients, as Ned mentioned. The enhancement request to add that support to the IMAP server is 16773916.