I have a need to localize the human-readable text inside of DSN's and
other automated responses to 822-format messages. Here is a proposal I
would like to float here, prior to issuing an internet-draft.
Define an "Accept-Language" header with the following syntax.
accept-language = "Accept-Language" ":" 1#Language-tag
; Language-tag as defined in RFC 1766
This header discloses the language preference(s) of the sender.
Languages listed earlier in the list are preferred.
The existence of this header also indicates that the sender is capable
of handling text encoded in the utf-8 charset [RFC 2044], when properly
The syntax of this header is deliberately a subset of that in HTTP.
Since this header is presumably only going to be generated by "new"
UA's, it is not unreasonable to require these "new" UA's to support
UTF-8. The alternative of also negotiating acceptable charset is worse.
Does not necessarily work correctly if the message goes through list
expansion. The language preferences of the list maintainer can be
different than those of the original sender, so if the list expander
does not know to strip or replace the Accept-Language header, the list
maintainer could get DSN's in a language and charset they don't
So, what do people think?