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Selection of Language for Internet Media

Document Charter Selection of Language for Internet Media WG (slim)
Title Selection of Language for Internet Media
Last updated 2018-01-30
State Approved
WG State Concluded
IESG Responsible AD Alexey Melnikov
Charter edit AD Alexey Melnikov
Send notices to (None)


A mutually comprehensible language is helpful for human communication.
This is true across a range of circumstances and environments. In
general, the problem is most acute in situations where there is not a
clear choice for a single language, such as environments lacking
contextual or out-of-band information regarding the identity of the
parties and the language to be used.

The group will address two specific cases that most urgently need a
technical solution: One problem space is non-real-time communication,
specifically email for one-to-many or where the set of recipients is
dynamic or different recipients require different languages; the other
is real-time communication, specifically emergency calling, preferably
also useful for other cases where the parties may not know each other
personally or where one party wishes to accommodate people with varying
language and media needs.

In the real-time communication case, language and media are
intrinsically linked, for example, signed languages require a video

While the two use cases are in different contexts (real time and
non-real-time), the fundamental goal is the same: to enable selection of
the best-fit language(s) for a specific situation. Some of the details
will also be in common across the cases, e.g., the language tags.
Having a single WG address both cases makes it clear that these are two
aspects of the same basic problem. A single WG also makes it easier to
maximize similarities and avoid unnecessary fragmentation of the
solutions and facilitates broader review.

The group will start by producing specifications for email and for
real-time communications.

In the email case, the group will determine a MIME based solution (based
on draft-tomkinson-slim-multilangcontent) that enables a single email
message to contain multiple language versions of the content, with
provisions to help clients select a best-fit version.

In the real-time communication case, the group will produce a
specification (based on draft-gellens-slim-negotiating-human-language)
enabling negotiation of a human language per media stream. The
specification must be suitable for use in emergency communications as
specified in RFC 6443 and RFC 6881 (which use SIP and SDP to negotiate
media); it is desirable to also be suitable for use in non-emergency
real-time communications that share the same call set-up and media
negotiation protocols. The mechanism will permit the caller's media and
language needs and preferences to be matched against what the called
party is able to provide. Alternatives such as doing the media
negotiation in SIP have been explored in the past and are out of scope
(although SIP-based mechanisms may be introduced when routing
considerations are addressed).

The group's initial focus will not be on supporting language-based call
routing decisions. Once the initial work is sufficiently progressed, the
group may address call routing, with the timing at the judgment of the

Recognizing that complex solutions are significantly less
likely to see widespread deployment, the group will solve the most
common use cases and avoid adding complexity to solve edge or
less-common cases.

By adding language to the existing media negotiation mechanism as used
in RFC 6443 and RFC 6881, the group can meet the basic use cases with
minimal added complexity and be able to enhance later for additional use
cases as needed.