Please add or modify the following items in the XML source code for this file before depositing the document in the IANA Repository. (https://www.iana.org/domains/idn-tables)
Note: version numbers start at 1. RFC 7940 recommends using simple integers. The version comment is optional, please replace or delete the default comment. Version comments may be used by some tools as part of the page header.
<version comment="[Please replace (or delete) the optional comment]">[Please fill in version number, starting at 1]</version>
<date>[Please fill in with publication date, in YYYY-MM-DD format]</date>
<validity-start>[Please fill in effective date, in YYYY-MM-DD format]</validity-start>
Note: the scope element may be repeated, so that the same document can serve for multiple domains.
<scope type="domain">[Please provide, in ".domain" format]</scope>
Registry Contact Information:
Please fill in the Registry Contact Details.
Change History
If you made technical modifications to the LGR, please summarize them in the Change History (and also note the details in the appropriate section of the description).
PLEASE DELETE THESE INSTRUCTIONS BEFORE DEPOSITING THE DOCUMENT
This document specifies a set of Label Generation Rules (LGR) for the English language using a language-specific repertoire for the second level domain or domains identified above. The format of this file follows [RFC 7940]. This LGR is adapted from the “Reference LGR for the Second Level for the English Language” [Ref-LGR-en-Latn], for details, see Change History below.
Standalone LGR: This LGR is designed to be used in a zone that does not cater to IDNs other than those valid under this LGR. This LGR lacks features that would allow its use in the context of another LGR in the same zone, and it may contain other features incompatible with such use.
All references converge on 26 Latin code points as minimal requirement for English. This requirement can be met with non-IDN labels. However, a limited number of accented letters and other forms are in reasonably prevalent use, whether for spelling loan words or names. Their use is optional in the orthography, and they are treated as “extended” code points here, which can be made available as described below.
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 undocumented local factors making them unreliable guides for IDN extension.
Letters documented in some references but not included:
U+00E3 LATIN SMALL LETTER A WITH TILDE
U+00E5 LATIN SMALL LETTER A WITH RING ABOVE
U+00EC LATIN SMALL LETTER I WITH GRAVE
U+00F0 LATIN SMALL LETTER ETH
U+00F2 LATIN SMALL LETTER O WITH GRAVE
U+00F8 LATIN SMALL LETTER O WITH STROKE
U+00F9 LATIN SMALL LETTER U WITH GRAVE
U+00FE LATIN SMALL LETTER THORN
U+00FF LATIN SMALL LETTER Y WITH DIAERESIS
U+0101 LATIN SMALL LETTER A WITH MACRON
U+0103 LATIN SMALL LETTER A WITH BREVE
U+0113 LATIN SMALL LETTER E WITH MACRON
U+0115 LATIN SMALL LETTER E WITH BREVE
U+012B LATIN SMALL LETTER I WITH MACRON
U+012D LATIN SMALL LETTER I WITH BREVE
U+014D LATIN SMALL LETTER O WITH MACRON
U+014F LATIN SMALL LETTER O WITH BREVE
U+0161 LATIN SMALL LETTER S WITH CARON
U+016B LATIN SMALL LETTER U WITH MACRON
U+016D LATIN SMALL LETTER U WITH BREVE
U+01BF LATIN LETTER WYNN
U+021D LATIN SMALL LETTER YOGH
U+1E13 LATIN SMALL LETTER D WITH CIRCUMFLEX BELOW
U+1E3D LATIN SMALL LETTER L WITH CIRCUMFLEX BELOW
U+1E45 LATIN SMALL LETTER N WITH DOT ABOVE
U+1E4B LATIN SMALL LETTER N WITH CIRCUMFLEX BELOW
U+1E71 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 such 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, code points 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 LATIN SMALL LETTER I WITH ACUTE and U+00FA LATIN SMALL LETTER U WITH ACUTE which were added to the extended set because of their use in Irish names.
Historically, no variants have been defined between any of the ASCII characters forming the repertoire for non-IDN labels. However, for IDN labels, variants may exist between ASCII and other characters. This LGR defines the variants described here for the extended code points, but they have no effect unless those characters are enabled.
In English usage the diaeresis, in particular, is not consistently employed and therefore something like a free spelling variant that is not consciously registered by most users. In fanciful usage, it is even treated like a decoration. Omitting it usually does not change the meaning of a word.
By default, this LGR treats all forms of a label with or without the diaeresis as optionally-enabled variants which would prevent them from being delegated to two different entities simultaneously. In order to restrict the number of allocatable variants, only one accented form can be allocated alongside the non-accented form. If the desired accented form has been applied for, the non-accented form would then be a variant that is allocatable to the original applicant. This covers the most common scenario of a single “correct” accented form, plus a non-accented “fallback”.
For example, this means that if a label like “naïve” is applied for, the label “naive” would be allocatable; alternatively, if the label “naive” is applied for, the label “naïve” would be blocked.
This extension to in-language variants is not compatible with using this LGR in a zone with another LGR and using the Common LGR to process conflicts between labels from multiple LGRs as described in Section 3 “Use of Multiple Reference LGRs in the Same Zone” in [Level-2-Overview].
No other variants are applicable when using the LGR in a standalone fashion.
Variants Limited to Standalone Use This LGR is not intended for use with LGRs for other languages or scripts in the same zone. The LGR does not define any “blocked” variants with code points in other languages or script that would prevent malicious registration of duplicate labels perceived as the same by users. As a result of transitivity, the scheme of internal variants defined here would have to be imposed on other LGRs that contain copies or variants of the affected code points.
If it is desired to support multiple languages in the same zone, the preferred method would be to support the corresponding script LGRs, which cater to the use of multiple languages, and are designed with the possibility of concurrent use in mind.
Certain variants in this LGR are defined as optionally enabled. They are using the context rule “enabled”. This context rule matches any label (it always succeeds). Any variant marked with when=“enabled” (in the XML file) is in force, while marking it with not-when=“enabled” causes the variant definition to be ignored in processing. This allows these variants to be disabled, for example, to better match legacy practice for a given zone.
Care must be taken to enable or disable variants so that all variant mappings to and from the same code point are either enabled or disabled at the same time, ensuring that all enabled variant mappings remain symmetric and transitive.
The specification of variants in this LGR follows the guidelines in [RFC 8228].
This LGR does not define named character classes.
The LGR includes the rules and actions to implement the following restrictions, some of which are mandated by the IDNA protocol. They are marked with ⍟ and included here by default. A special context rule enables optional variants by default.
when="enabled" in the xml will be active, while any with not-when="enabled" will be inactive.This LGR includes the default actions for LGRs as well as the action needed to invalidate labels with misplaced combining marks. They are marked with ⍟. For a description see [RFC 7940].
Because this LGR defines allocatable fallback variants the following default actions are applicable.
These actions resolve as “allocatable” any label where all variants are of type “fallback”, and as “valid” any label where all variants are of type “r-original”. Labels with a mix of variant types are resolved as “blocked”.
To account for original code points in a permuted variant, reflexive variant mappings with an “r-” prefix are used. (See [RFC 7940]). In particular, the mapping type “r-original” is given to any code point that has a fallback mapping, but that appears in its non-fallback form in the original label, and thus “maps to itself”.
Default actions that are triggered by the LGR-specific variant types described above limit the “allocatable” variant labels to those variants resulting from removal of the diaeresis, while disallowing mixed use of variants with or without diaeresis, except as in the original applied-for label. The use of such variants is "optionally_enabled_variants">optionally enabled in this LGR.
Note that the mapping types for variants are not symmetric: they depend on which code point is considered the source or the target in a given mapping. As specified in [RFC 7940], when mapping types are evaluated code points in a label that are unchanged use the type of their “reflexive” mapping. Per [RFC 7940] the actions are always applied one after the other, and the evaluation stops at the first action that assigns a disposition to a given label.
The LGR in this document has been adapted from the corresponding Reference LGR for the Second Level. The Second Level Reference LGR for the English Language was developed by Michel Suignard and Asmus Freytag, including input by Michael Everson, Nicholas Ostler, and Wil Tan, and based on multiple open public consultations.
Language tag has been updated.
Unicode Version has been updated.
Based on further review in connections with updates to the reference LGR for the French language [Ref-LGR-fr], the addition of fallback variants between letters with diaeresis and their ASCII base letters appears indicated. These variants are enabled here by default, but are marked as “enabled” to allow registries to deactivate them if required.
Adopted from the Second Level Reference LGR for the English Language [Ref-LGR-en-Latn] without normative changes.
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”, https://en.wikipedia.org/wiki/English_alphabet
In addition, the following references were consulted:
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. Entries in the table may have multiple source reference values. In the listing of whole label evaluation and context rules, reference [150] indicates the source for common rules. For more details, see the Table of References below.
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