Content-Language, Accept-Language
Network Working Group H. Alvestrand
Request for Comments: 3282 Cisco Systems
Obsoletes: 1766 May 2002
Category: Standards Track
<!ENTITY ja.mail.header "頭">
Content Language Headers
内容言語&ja.mail.header;
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
This document defines a "Content-language:" header, for use in cases
where one desires to indicate the language of something that has RFC
822-like headers, like MIME body parts or Web documents, and an
"Accept-Language:" header for use in cases where one wishes to
indicate one's preferences with regard to language.
<!ENTITY ja.mime.body-part "本文部分">
この文書は "Content-language:" &ja.mail.header;を MIME &ja.mime.body-part;や
Web 文書のような RFC 822 的&ja.mail.header;を持つものの言語を示したい場合に使うのに、また
"Accept-Language:" &ja.mail.header;を言語に関する好みを示したいと願う場合に使うのに定義します。
1. Introduction
There are a number of languages presently or previously used by human
beings in this world.
現在あるいは過去にこの世界において人間により数多くの言語が使われて来ました。
A great number of these people would prefer to have information
presented in a language which they understand.
多数の人々は、その理解する言語により表現された情報を手にすることをより望むことでしょう。
In some contexts, it is possible to have information available in
more than one language, or it might be possible to provide tools
(such as dictionaries) to assist in the understanding of a language.
幾つかの場面で、情報を複数の言語で利用可能とすることが出来たり、言語を理解する上で補助する道具
(例えば辞書) を提供することが可能であったりするかもしれません。
In other cases, it may be desirable to use a computer program to
convert information from one format (such as plaintext) into another
(such as computer-synthesized speech, or Braille, or high-quality
print renderings).
<!ENTITY ja.plain-text "平文">
<!ENTITY ja.rendering "レンダリング">
この他、計算機プログラムを、ある形式 (例えば&ja.plain-text;)
から他の形式 (計算機合成話, 点字, 高品質印刷&ja.rendering;など)
に情報を変換する計算機プログラムを使うことが望ましいかもしれません。
A prerequisite for any such function is a means of labelling the
information content with an identifier for the language that is used
in this information content, such as is defined by [TAGS]. This
document specifies a protocol element for use with protocols that use
RFC 822-like headers for carrying language tags as defined in [TAGS].
このような機能には、その情報内容中で使われている言語の, [TAGS]
で定義されているような識別子で情報内容を札付けする必要があります。この文書は、
RFC 822 的&ja.mail.header;を使う&ja.protocol;で [TAGS]
で定義された言語札を運ぶ&ja.protocol;要素を規定します。
<!ENTITY ja.protocol "プロトコル">
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC 2119].
この文書中で、用語
は
で説明されているように解釈するものとします。
2. The Content-language header
The "Content-Language" header is intended for use in the case where
one desires to indicate the language(s) of something that has RFC
822-like headers, such as MIME body parts or Web documents.
"Content-Language" &ja.mail.header;は、 MIME &ja.mime.body-part;や
Web 文書のように、 RFC 822
的&ja.mail.header;を持つものの言語を示したい時に使うことを意図しています。
The RFC 822 EBNF of the Content-Language header is:
Content-Language &ja.mail.header;の RFC 822 EBNF は次の通りです。
Content-Language = "Content-Language" ":" 1#Language-tag
In the more strict RFC 2234 ABNF:
より厳密な RFC 2234 ABNF では次の通りです。
Content-Language = "Content-Language" ":" [CFWS] Language-List
Language-List = Language-Tag [CFWS]
*("," [CFWS] Language-Tag [CFWS])
The Content-Language header may list several languages in a comma-
separated list.
Content-Language &ja.mail.header;では、読点 (comma)
区切りの一覧の形で複数の言語を列挙出来ます。
The CFWS construct is intended to function like the whitespace
convention in RFC 822, which means also that one can place
parenthesized comments anywhere in the language sequence, or use
continuation lines. A formal definition is given in RFC 2822
[RFC2822].
CFWS 構造は、 RFC 822 の&ja.whitespace;記法の様に機能することを想定しています。ですから括弧で括った注釈を言語列中のどこにでも置くことが出来ますし、継続行を使うことも出来ます。正式な定義は
RFC 2822 中にあります。
In keeping with the tradition of RFC 2822, a more liberal "obsolete"
grammar is also given:
RFC 2822 の伝統を受け継ぎ、より寛大な「時代遅れ」文法も示します。
obs-content-language = "Content-Language" *WSP ":"
[CFWS] Language-List
Like RFC 2822, this specification says that conforming
implementations MUST accept the obs-content-language syntax, but MUST
NOT generate it; all generated headers MUST conform to the Content-
Language syntax.
RFC 2822 同様、適合する実装は obs-content-language
構文を受け付けja:MUSTなければなりません</ja:MUST>が、生成ja:MUSTNOTしてはならない</ja:MUSTNOT>ことをこの規定は示しています。生成する全ての&ja.mail.header;は、
Content-Language 構文に適合しja:MUSTなければなりません</ja:MUST>。
2.1 Examples of Content-language values
Content-language 値の例
Voice recording from Liverpool downtown
Liverpool 下町での音声録音
Content-type: audio/basic
Content-Language: en-scouse
Document in Mingo, an American Indian language which does not have an
ISO 639 code:
Mingo (亜米利加インディアン言語で、 ISO 639 &ja.lang.code;を持たない。)
で書かれた文書
Content-type: text/plain
Content-Language: i-mingo
A English-French dictionary
英仏辞典
Content-type: application/dictionary
Content-Language: en, fr (This is a dictionary)
(これは辞書です)
An official European Commission document (in a few of its official
languages):
欧州委員会の公式文書 (その公用語の幾つかで)
Content-type: multipart/alternative
Content-Language: da, de, el, en, fr, it
An excerpt from Star Trek
Star Trek からの抜粋
Content-type: video/mpeg
Content-Language: i-klingon
3. The Accept-Language header
The "Accept-Language" header is intended for use in cases where a
user or a process desires to identify the preferred language(s) when
RFC 822-like headers, such as MIME body parts or Web documents, are
used.
"Accept-Language" 頭は、MIME &ja.mime.body-part;や
Web 文書のような RFC 822 的&ja.mail.header;を持つもので、利用者や処理が、好ましい言語を示したい場合に使うことを意図しています。
The RFC 822 EBNF of the Accept-Language header is:
Accept-Language &ja.header;の RFC 822 EBNF は次の通りです。
Accept-Language = "Accept-Language" ":"
1#( language-range [ ";" "q" "=" qvalue ] )
A slightly more restrictive RFC 2234 ABNF definition is:
より厳密な RFC 2234 ABNF の定義は次の通りです。
Accept-Language = "Accept-Language:" [CFWS] language-q
*( "," [CFWS] language-q )
language-q = language-range [";" [CFWS] "q=" qvalue ] [CFWS]
qvalue = ( "0" [ "." 0*3DIGIT ] )
/ ( "1" [ "." 0*3("0") ] )
A more liberal RFC 2234 ABNF definition is:
より寛大な RFC 2234 ABNF 定義は次の通りです。
Obs-accept-language = "Accept-Language" *WSP ":" [CFWS]
obs-language-q *( "," [CFWS] obs-language-q ) [CFWS]
obs-language-q = language-range
[ [CFWS] ";" [CFWS] "q" [CFWS] "=" qvalue ]
Like RFC 2822, this specification says that conforming
implementations MUST accept the obs-accept-language syntax, but MUST
NOT generate it; all generated messages MUST conform to the Accept-
Language syntax.
RFC 2822 同様、適合する実装は obs-accept-language
構文を受け付けja:MUSTなければなりません</ja:MUST>が、生成ja:MUSTNOTしてはならない</ja:MUSTNOT>ことをこの規定は示しています。生成する全ての&ja.mail.header;は、
Accept-Language 構文に適合しja:MUSTなければなりません</ja:MUST>。
The syntax and semantics of language-range is defined in [TAGS]. The
Accept-Language header may list several language-ranges in a comma-
separated list, and each may include a quality value Q. If no Q
values are given, the language-ranges are given in priority order,
with the leftmost language-range being the most preferred language;
this is an extension to the HTTP/1.1 rules, but matches current
practice.
language-range の構文と意味は [TAGS] で定義しています。
Accept-Language &ja.mail.header;は、読点 (comma)
で区切った一覧の形で複数の language-range を列挙しても構いません。それぞれは資質値
Q を含んでも構いません。 Q 値が与えられていない場合、
language-range は優先順に与えられ、一番左の language-range
が最優先の言語となります。これは HTTP/1.1 の規則の拡張ですが、現在の慣習と一致しています。
If Q values are given, refer to HTTP/1.1 [RFC 2616] for the details
on how to evaluate it.
Q 値が与えられている場合、どう評価するかの詳細については HTTP/1.1
を御覧下さい。
4. Security Considerations
The only security issue that has been raised with language tags since
the publication of RFC 1766, which stated that "Security issues are
believed to be irrelevant to this memo", is a concern with language
ranges used in content negotiation - that they may be used to infer
the nationality of the sender, and thus identify potential targets
for surveillance.
<!ENTITY ja.security "安全性">
<!ENTITY ja.lang.tag "札">
<!ENTITY ja.conneg "内容折衝">
「&ja.security;問題はこのメモと関係ないと信じています」とした
RFC 1766 の出版以降言語&ja.lang.tag;に関して起こった唯一の&ja.security;問題は、&ja.conneg;において使われる言語範囲に関してです。これは送信者の民族を推察するのに使われ得るので、潜在的監視対象を特定することになり得ます。
This is a special case of the general problem that anything you send
is visible to the receiving party; it is useful to be aware that such
concerns can exist in some cases.
これは、送信したものは受信者側に見えてしまう、一般的問題の特殊な場合です。このような心配が幾つかの場合に存在し得ることを意識しておくのが良いでしょう。
The exact magnitude of the threat, and any possible countermeasures,
is left to each application protocol.
<!ENTITY ja.application "応用">
実際の脅威の大きさや可能な対応策については、各&ja.application;&ja.protocol;に任せます。
5. Character set considerations
This document adds no new considerations beyond what is mentioned in
[TAGS].
この文書では TAGS で挙げたもの以外に追加の考慮事項はありません。
6. Acknowledgements
This document has benefited from many rounds of review and comments
in various fora of the IETF and the Internet working groups.
この文書は、 IETF と Internet 作業部会の各種討論場にでの多段階にわたる批評から利益を得ました。
Any list of contributors is bound to be incomplete; please regard the
following as only a selection from the group of people who have
contributed to make this document what it is today.
どんな貢献者の一覧を作っても不完全になってしまいます。次に挙げたものは、この文書が今日のこの姿にするのに貢献して下さった人々の集団から選んだ人々だけであると考えて下さい。
In alphabetical order:
字母順
Tim Berners-Lee, Nathaniel Borenstein, Sean M. Burke, John Clews, Jim
Conklin, John Cowan, Dave Crocker, Martin Duerst, Michael Everson,
Ned Freed, Tim Goodwin, Dirk-Willem van Gulik, Marion Gunn, Paul
Hoffman, Olle Jarnefors, John Klensin, Bruce Lilly, Keith Moore,
Chris Newman, Masataka Ohta, Keld Jorn Simonsen, Rhys Weatherley,
Misha Wolf, Francois Yergeau and many, many others.
Special thanks must go to Michael Everson, who has served as language
tag reviewer for almost the entire period, since the publication of
RFC 1766, and has provided a great deal of input to this revision.
Bruce Lilly did a special job of reading and commenting on my ABNF
definitions.
<!ENTITY ja.ietf.reviewer "評論者">
<!ENTITY ja.lang.code "符号">
Michael Everson には特に感謝しなければなりません。彼は、
RFC 1766 の出版からほとんど全期間&ja.lang.tag;&ja.ietf.reviewer;を務めて下さり、この改訂にも大変多くの意見を下さいました。
Bruce Lilly は、私の ABNF 定義を読んで評価するという特別な仕事をして下さいました。
7. References
[TAGS] Alvestrand, H., "Tags for the Identification of
Languages", BCP 47, RFC 3066
言語識別用の&ja.lang.tag;
[ISO 639] ISO 639:1988 (E/F) - Code for the representation of names
of languages - The International Organization for
Standardization, 1st edition, 1988-04-01 Prepared by
ISO/TC 37 - Terminology (principles and coordination).
Note that a new version (ISO 639-1:2000) is in
preparation at the time of this writing.
言語名&ja.lang.code;
用語 (原則及び調整)
<!-- http://www.jisc.go.jp/international/iso-tc.html -->
<!-- JIS にない?? -->
なお、執筆の時点で新版 (ISO 639-1:2000) が準備中。
[ISO 639-2] ISO 639-2:1998 - Codes for the representation of names of
languages -- Part 2: Alpha-3 code - edition 1, 1998-11-
01, 66 pages, prepared by ISO/TC 37/SC 2
[ISO 3166] ISO 3166:1988 (E/F) - Codes for the representation of
names of countries - The International Organization for
Standardization, 3rd edition, 1988-08-15.
国名コード
<!-- JIS X 0304:1999 / ISO 3166-1:1997 -->
[ISO 15924] ISO/DIS 15924 - Codes for the representation of names of
scripts (under development by ISO TC46/SC2)
用字系名&ja.lang.code;
(ISO TC46/SC2 で開発中)
[RFC 2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
<!ENTITY ja.mime.fullname "多目的 Internet メイル拡張">
&ja.mime.fullname; (MIME)
[RFC 2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC 2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII
Text", RFC 2047, November 1996.
[RFC 2048] Freed, N., Klensin, J. and J. Postel, "Multipurpose
Internet Mail Extensions (MIME) Part Four: Registration
Procedures", RFC 2048, November 1996.
[RFC 2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Five: Conformance Criteria and
Examples", RFC 2049, November 1996.
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
RFC 中で要求水準を示すのに使うキーワード
[RFC 2234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
[RFC 2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC 2822] Resnick, P., "Internet Message Format", RFC 2822, April
2001.
Appendix A: Changes from RFC 1766
The definition of the language tags has been split, and is now RFC
3066. The differences parameter to multipart/alternative is no
longer part of this standard, because no implementations of the
function were ever found. Consult RFC 1766 if you need the
information.
言語&ja.lang.tag;の定義は分離して、 RFC 3066 となりました。
multipart/alternative の differences (差異) パラメータは、この機能の実装が無かったので、この規格の部分では失くしました。もし情報が必要であれば、
RFC 1766 を御覧下さい。
The ABNF for content-language has been updated to use the RFC 2234 ABNF.
content-language の ABNF を RFC 2234 ABNF に更新しました。
Author's Address
Harald Tveit Alvestrand
Cisco Systems
Weidemanns vei 27
7043 Trondheim
NORWAY
EMail: Harald@Alvestrand.no
Phone: +47 73 50 33 52
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