Is there a way to provide localized versions of the Debian packaging control files (changelog, control and copyright for example) ?
The format is laid down in the Debian Policy Manual, chapters 4 and 5. I don't see any provision for localisation. I suspect this is because control and changelog are heavily machine-parsed; allowing the field names to change risks vastly overcomplicating the mechanisms which deal with them. It is a bad idea to localise copyright because that is supposed to be a verbatim copy of the upstream package's copyright declaration: also, being a legal document, translating it is risky.
Besides, most users never see these files. Why do you want to localise them?