This document is mechanically formatted from the XML file for the LGR. It provides additional summary data and explanatory text. The XML file remains the sole normative specification of the LGR.
Date | 2016-08-30 |
---|---|
LGR Version | 1 |
Language | eng-Latn |
Unicode Version | 6.3.0 |
This document specifies a reference set of Label Generation Rules for English using a limited repertoire as appropriate for a second level domain.
All references converge on 26 Latin code points.
The range of ccTLDs with English as a native language is extensive. However, their requirements for letters outside the standard alphabet are expected to be affected by local factors thus making them unreliable guides for IDN extension.
Letters documented in some references but not included:
U+00E3 (ã) LATIN SMALL LETTER A WITH TILDE
U+00E5 (å) LATIN SMALL LETTER A WITH RING ABOVE
U+00EC (ì) LATIN SMALL LETTER I WITH GRAVE
U+00F0 (ð) LATIN SMALL LETTER ETH
U+00F2 (ò) LATIN SMALL LETTER O WITH GRAVE
U+00F8 (ø) LATIN SMALL LETTER O WITH STROKE
U+00F9 (ù) LATIN SMALL LETTER U WITH GRAVE
U+00FE (þ) LATIN SMALL LETTER THORN
U+00FF (ÿ) LATIN SMALL LETTER Y WITH DIAERESIS
U+0101 (ā) LATIN SMALL LETTER A WITH MACRON
U+0103 (ă) LATIN SMALL LETTER A WITH BREVE
U+0113 (ē) LATIN SMALL LETTER E WITH MACRON
U+0115 (ĕ) LATIN SMALL LETTER E WITH BREVE
U+012B (ī) LATIN SMALL LETTER I WITH MACRON
U+012D (ĭ) LATIN SMALL LETTER I WITH BREVE
U+014D (ō) LATIN SMALL LETTER O WITH MACRON
U+014F (ŏ) LATIN SMALL LETTER O WITH BREVE
U+0161 (š) LATIN SMALL LETTER S WITH CARON
U+016B (ū) LATIN SMALL LETTER U WITH MACRON
U+016D (ŭ) LATIN SMALL LETTER U WITH BREVE
U+01BF (ƿ) LATIN LETTER WYNN
U+021D (ȝ) LATIN SMALL LETTER YOGH
U+1E13 (ḓ) LATIN SMALL LETTER D WITH CIRCUMFLEX BELOW
U+1E3D (ḽ) LATIN SMALL LETTER L WITH CIRCUMFLEX BELOW
U+1E45 (ṅ) LATIN SMALL LETTER N WITH DOT ABOVE
U+1E4B (ṋ) LATIN SMALL LETTER N WITH CIRCUMFLEX BELOW
U+1E71 (ṱ) LATIN SMALL LETTER T WITH CIRCUMFLEX BELOW
A number of letters not considered essential to writing the core vocabulary of the language are nevertheless in common use. Where they have not been added to the core repertoire, they are flagged as "extended-cp" in the table of code points. A context rule is provided that by default will prohibit labels with extended code points. To support extended single code points or code point sequences, delete the context "extended-cp" from their repertoire definition.
As the native vocabulary of English is commonly written with only the core alphabet of 26 Basic Latin letters, the main rationale for developing an LGR that covers IDNs is to be able to write loan words. This might argue for including the extensions by default in the LGR. However, there is no clear consensus on what constitutes a core set of extensions, and there are regional differences in their use. As a result, extensions with multiple sources have been marked as extended, while code points with fewer sources are listed above in the excluded set. The exception are U+00ED (í) LATIN SMALL LETTER I WITH ACUTE and U+00FA (ú) LATIN SMALL LETTER U WITH ACUTE which were added to the extended set because of Irish names.
None.
This LGR defines no named character classes.
Common rules only:
Hyphen Restrictions — restrictions on the allowable placement of hyphens (no leading/ending hyphen and no hyphen in positions 3 and 4). These restrictions are described in section 4.2.3.1 of RFC5891 [120]. They are implemented here as context rule on U+002D (-) (-) HYPHEN-MINUS.
Leading Combining Marks — restrictions on the allowable placement of combining marks (no leading combining mark). This rule is described in section 4.2.3.2 of RFC5891 [120].
Actions included are the default actions for LGRs as well as those needed to invalidate labels with misplaced combining marks.
This reference LGR for English for the 2nd Level has been developed by Michel Suignard and Asmus Freytag, verified in expert reviews by Michael Everson, Nicholas Ostler, and Wil Tan, and based on multiple open public consultations.
General references for the language:
Allen, R. E., ed. 1990. The concise Oxford dictionary of current English. 8th ed. Oxford: Clarendon Press. ISBN 0-19-861200-1
Bringhurst, Robert. 1997. The elements of typographic style. 2nd ed. Point- Roberts, WA; Vancouver, BC: Hartley & Marks. ISBN 0-88179-133-4
Wikipedia: "English alphabet",
http://en.wikipedia.org/wiki/English_alphabet
In the listing of the repertoire by code point, references starting from [0] refer to the version of the Unicode Standard in which the corresponding code point was initially encoded. Other references (starting from [100]) document usage of code points. For more details, see the Table of References below.
Number of elements in Repertoire | 37 |
---|---|
Number of extended elements | 21 |
Total entries in table | 58 |
Longest code point sequence | 1 |
The following table lists the repertoire by code point (or code point sequence). The data in the Script and Name column are extracted from the Unicode character database. Where a comment in the original LGR is equal to the character name, it has been suppressed.
Code Point |
Glyph | Script | Name | References | Tags | Required Context | Part of Repertoire |
Comment |
---|---|---|---|---|---|---|---|---|
U+002D | - | Common | HYPHEN-MINUS | [0], [100], [301], [401], [601] | sc:Zyyy | not: hyphen-minus-disallowed | ✔ | |
U+0030 | 0 | Common | DIGIT ZERO | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0031 | 1 | Common | DIGIT ONE | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0032 | 2 | Common | DIGIT TWO | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0033 | 3 | Common | DIGIT THREE | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0034 | 4 | Common | DIGIT FOUR | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0035 | 5 | Common | DIGIT FIVE | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0036 | 6 | Common | DIGIT SIX | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0037 | 7 | Common | DIGIT SEVEN | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0038 | 8 | Common | DIGIT EIGHT | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0039 | 9 | Common | DIGIT NINE | [0], [100], [301], [401], [601] | sc:Zyyy | ✔ | ||
U+0061 | a | Latin | LATIN SMALL LETTER A | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0062 | b | Latin | LATIN SMALL LETTER B | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0063 | c | Latin | LATIN SMALL LETTER C | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0064 | d | Latin | LATIN SMALL LETTER D | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0065 | e | Latin | LATIN SMALL LETTER E | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0066 | f | Latin | LATIN SMALL LETTER F | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0067 | g | Latin | LATIN SMALL LETTER G | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0068 | h | Latin | LATIN SMALL LETTER H | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0069 | i | Latin | LATIN SMALL LETTER I | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+006A | j | Latin | LATIN SMALL LETTER J | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+006B | k | Latin | LATIN SMALL LETTER K | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+006C | l | Latin | LATIN SMALL LETTER L | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+006D | m | Latin | LATIN SMALL LETTER M | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+006E | n | Latin | LATIN SMALL LETTER N | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+006F | o | Latin | LATIN SMALL LETTER O | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0070 | p | Latin | LATIN SMALL LETTER P | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0071 | q | Latin | LATIN SMALL LETTER Q | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0072 | r | Latin | LATIN SMALL LETTER R | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0073 | s | Latin | LATIN SMALL LETTER S | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0074 | t | Latin | LATIN SMALL LETTER T | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0075 | u | Latin | LATIN SMALL LETTER U | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0076 | v | Latin | LATIN SMALL LETTER V | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0077 | w | Latin | LATIN SMALL LETTER W | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0078 | x | Latin | LATIN SMALL LETTER X | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+0079 | y | Latin | LATIN SMALL LETTER Y | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+007A | z | Latin | LATIN SMALL LETTER Z | [0], [100], [301], [401], [601] | sc:Latn | ✔ | ||
U+00E0 | à | Latin | LATIN SMALL LETTER A WITH GRAVE | [0], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E1 | á | Latin | LATIN SMALL LETTER A WITH ACUTE | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E2 | â | Latin | LATIN SMALL LETTER A WITH CIRCUMFLEX | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E4 | ä | Latin | LATIN SMALL LETTER A WITH DIAERESIS | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E6 | æ | Latin | LATIN SMALL LETTER AE | [0], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E7 | ç | Latin | LATIN SMALL LETTER C WITH CEDILLA | [0], [100], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E8 | è | Latin | LATIN SMALL LETTER E WITH GRAVE | [0], [200], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00E9 | é | Latin | LATIN SMALL LETTER E WITH ACUTE | [0], [100], [200], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00EA | ê | Latin | LATIN SMALL LETTER E WITH CIRCUMFLEX | [0], [200], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00EB | ë | Latin | LATIN SMALL LETTER E WITH DIAERESIS | [0], [100], [200], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00ED | í | Latin | LATIN SMALL LETTER I WITH ACUTE | [0], [402] | sc:Latn | extended-cp | ◯ | |
U+00EE | î | Latin | LATIN SMALL LETTER I WITH CIRCUMFLEX | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00EF | ï | Latin | LATIN SMALL LETTER I WITH DIAERESIS | [0], [100], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00F1 | ñ | Latin | LATIN SMALL LETTER N WITH TILDE | [0], [301], [402] | sc:Latn | extended-cp | ◯ | |
U+00F3 | ó | Latin | LATIN SMALL LETTER O WITH ACUTE | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00F4 | ô | Latin | LATIN SMALL LETTER O WITH CIRCUMFLEX | [0], [100], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00F6 | ö | Latin | LATIN SMALL LETTER O WITH DIAERESIS | [0], [100], [301], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00FA | ú | Latin | LATIN SMALL LETTER U WITH ACUTE | [0], [402] | sc:Latn | extended-cp | ◯ | |
U+00FB | û | Latin | LATIN SMALL LETTER U WITH CIRCUMFLEX | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+00FC | ü | Latin | LATIN SMALL LETTER U WITH DIAERESIS | [0], [402], [604] | sc:Latn | extended-cp | ◯ | |
U+0153 | œ | Latin | LATIN SMALL LIGATURE OE | [0], [301], [402], [604] | sc:Latn | extended-cp | ◯ |
This LGR does not specify any variants.
The following table lists all named classes with their definition and a list of their members intersected with the current repertoire (for larger classes, this list is elided).
Name | Definition | Count | Members or Ranges | Ref | Comment |
---|---|---|---|---|---|
implicit | Tag=sc:Latn | 47 Elements: | {0061-007A 00E0-00E2 00E4 00E6-00EB 00ED-00EF 00F1 00F3-00F4 00F6 00FA-00FC 0153} | ||
implicit | Tag=sc:Zyyy | 11 Elements: | {002D 0030-0039} |
The following table lists all named rules defined in the LGR and indicates whether they are used as trigger in an action or as context (when or not-when) for a code point. (Any use of context rules for variants is not indicated).
Name | Used as Trigger |
Used as Context |
Anchor | Regular Expression | Ref | Comment |
---|---|---|---|---|---|---|
leading-combining-mark | ✔ | (^[∅=[[∅=\p{gc=Mn}][∅=\p{gc=Mc}]]]) |
[120] | RFC5891 restrictions on placement of combining marks | ||
hyphen-minus-disallowed | ✔ | ✔ | ((((?<=^)⚓)|(⚓(?=$))|((?<=^..\u002D)⚓))) |
[120] | RFC5891 restrictions on placement of U+002D | |
extended-cp | ✔ | (^$) |
code points from the extended range |
The following table lists the actions that are used to assign dispositions to labels and variant labels, based on the specified conditions. The order of actions defines their precedence: the first action triggered by a label is the one defining its disposition.
# | Condition | Rule / Variant Set | Disposition | Ref | Comment | |
---|---|---|---|---|---|---|
1 | if label matches | leading-combining-mark | → | invalid | by default, labels with leading combining marks are invalid | |
2 | if any label (catch-all) | → | valid | catch all |
[0] | The Unicode Consortium. The Unicode Standard, Version 6.3.0,
(Mountain View, CA: The Unicode Consortium, 2013. ISBN 978-1-936213-08-5)
http://www.unicode.org/versions/Unicode6.3.0/ Code points cited were originally encoded in Unicode Version 1.1 |
[100] | Internetstiftelsen i Sverige (IIS), "IDN Reference table for English language"
https://github.com/dotse/IDN-ref-tables/blob/master/language-tables/english-lang-ref-table.txt |
[120] | RFC5891, Internationalized Domain Names in Applications (IDNA): Protocol http://tools.ietf.org/html/rfc5891 |
[200] | ISO/IEC 6937 Third Ed. 2001-12-17- Information
technology — Coded graphic character set for text communication — Latin alphabet: Table D.1 (p 35) Use of Latin alphabetic characters. This table lists only the characters outside the set a-z |
[301] | Everson, Michael. The Alphabets of Europe: "English" http://www.evertype.com/alphabets/english.pdf Code points cited form the standard set |
[302] | Everson, Michael. The Alphabets of Europe: "English" http://www.evertype.com/alphabets/english.pdf Code points cited are from an extended set |
[304] | Everson, Michael. The Alphabets of Europe: "English" http://www.evertype.com/alphabets/english.pdf Code points cited are rare or archaic |
[401] | The Unicode Consortium, Common Locale Data Repository (CLDR) Version 28 (2015-09-16) -
Locale Data Summary forEnglish [en] http://www.unicode.org/cldr/charts/28/summary/en.html Code points cited are from the set of Main Letters |
[402] | The Unicode Consortium, Common Locale Data Repository (CLDR) Version 28 (2015-09-16) -
Locale Data Summary forEnglish [en] http://www.unicode.org/cldr/charts/28/summary/en.html Code points cited are from the Auxiliary set |
[403] | The Unicode Consortium, Common Locale Data Repository (CLDR) Version 28 (2015-09-16) -
Locale Data Summary for English [en] http://www.unicode.org/cldr/charts/28/summary/en.html Code points cited are from an extension for locale EN_ZA |
[601] | Wikipedia: "Latin Alphabets"
https://en.wikipedia.org/wiki/Latin_alphabets - accessed 2015-10-31 According to this reference, the alphabet is listed as using the full basic set A-Z |
[604] | Wikipedia: " Latin Alphabets" in https://en.wikipedia.org/wiki/Latin_alphabets accessed 2015-10-31 The table only lists code points beyond A-Z |
[605] | Wikipedia: "English orthography"
https://en.wikipedia.org/wiki/English_orthography Code points cited are listed as in extended use based on use of accent in loan words |