This document specifies a set of Label Generation Rules (LGR) for the Ukrainian 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 Ukrainian Language” [Ref-LGR-uk-Cyrl], 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.
Most references converge on 33 Cyrillic code points. There is some disagreement concerning U+044A CYRILLIC SMALL LETTER HARD SIGN and U+0451 CYRILLIC SMALL LETTER IO. While CLDR considers U+0451 CYRILLIC SMALL LETTER IO part of the main alphabet, these appear to be used in Russian words or names, not in Ukrainian words and names themselves. Both of these letters are part of the extended repertoire as defined here along with many letters used for Ukrainian. In Russian, the hard sign indicates the non-palatalization of a consonant preceding a morpheme beginning with a iotated vowel; in Ukrainian this function is met by the use of an apostrophe or of U+02BC MODIFIER LETTER APOSTROPHE.
Note that, while U+02BC MODIFIER LETTER APOSTROPHE is used in Ukrainian and is protocol valid (PVALID) in IDNA2008; other forms of apostrophes such as U+0027 APOSTROPHE or U+2019 RIGHT SINGLE QUOTATION MARK are DISALLOWED. As [RFC 6912] points out, in a public zone, many users may read U+02BC as indistinguishable from the regular apostrophe. Therefore, following the principle of conservatism, and in response to a comment made by the IAB during public comment proceedings, the code point U+02BC is not included here.
An IDN table published in the IANA Repository of IDN Practices for Ukrainian by .ua (Ukrainian cctld) in [700] contains many code points beyond what would be used in Ukrainian and even languages used in adjacent areas. Code points not corroborated by any other reference but used for Belarusian, Russian, and Moldovan have been added to the extended repertoire. South Slavic characters are excluded here.
For other IDNA TLD dedicated to Ukrainian: see .укр [YKP] and the IDNA table in [701]. That table shows a repertoire combining Russian and Ukrainian.
In Ukrainian, the acute accent may be used as a stress mark on the vowel of a syllable or to disambiguate between minimal pairs. However, as in Russian, it is restricted to dictionaries and educational materials. See Stress and Disambiguation in [ACUTE].
Letters documented in some references but not included:
U+02BC MODIFIER LETTER APOSTROPHE
U+0450 CYRILLIC SMALL LETTER IE WITH GRAVE
U+0452 CYRILLIC SMALL LETTER DJE
U+0453 CYRILLIC SMALL LETTER GJE
U+0455 CYRILLIC SMALL LETTER DZE
U+0458 CYRILLIC SMALL LETTER JE
U+0459 CYRILLIC SMALL LETTER LJE
U+045A CYRILLIC SMALL LETTER NJE
U+045B CYRILLIC SMALL LETTER TSHE
U+045C CYRILLIC SMALL LETTER KJE
U+045D CYRILLIC SMALL LETTER I WITH GRAVE
U+045F CYRILLIC SMALL LETTER DZHE
U+0430 U+0301 CYRILLIC SMALL LETTER A WITH ACUTE ACCENT
U+0435 U+0301 CYRILLIC SMALL LETTER IE WITH ACUTE ACCENT
U+0438 U+0301 CYRILLIC SMALL LETTER I WITH ACUTE ACCENT
U+043E U+0301 CYRILLIC SMALL LETTER O WITH ACUTE ACCENT
U+0443 U+0301 CYRILLIC SMALL LETTER U WITH ACUTE ACCENT
U+044E U+0301 CYRILLIC SMALL LETTER YU WITH ACUTE ACCENT
U+044F U+0301 CYRILLIC SMALL LETTER YA WITH ACUTE ACCENT
U+0454 U+0301 CYRILLIC SMALL LETTER UKRAINIAN IE WITH ACUTE ACCENT
U+0456 U+0301 CYRILLIC SMALL LETTER BYELORUSSIAN-UKRAINIAN I WITH ACUTE ACCENT
U+0457 U+0301 CYRILLIC SMALL LETTER YI WITH ACUTE ACCENT
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.
Any code points outside the Ukrainian Language repertoire that are targets for out-of-repertoire variants would be included here only if the variant is listed in this file. In this case they are identified as a reflexive (identity) variant of type “out-of-repertoire-var”. Whether or not they are listed, they do not form part of the repertoire.
There are no variants defined between Cyrillic letters.
No ASCII Variants: Note that this LGR does not contain definitions for “blocked” variants for letters that look indistinguishable from ASCII letters (homoglyphs). If concurrent use of LDH labels is desired, the resulting conflicts can be handled by using the “Common LGR” in processing. For details, see Section 3, “Use of Multiple Reference LGRs in the Same Zone” in [Level-2-Overview].
Note: a study of a possible variant relationship concerning U+0433 CYRILLIC SMALL LETTER GHE and U+0491 CYRILLIC SMALL LETTER GHE WITH UPTURN was undertaken in the context of Ukrainian by a Cyrillic case study team in [CYRILLIC-VIP] (page 6, section 3.2). The experts point to some instability concerning the encoding of the GHE WITH UPTURN and the possible confusion between the two code points by non-Ukrainian users. However, in the context of a Ukrainian LGR it does not seem necessary to establish such a variant relationship between these two code points.
This LGR does not define named character classes.
By default, the LGR includes the rules and actions to implement the following restrictions mandated by the IDNA protocol. They are marked with ⍟.
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].
The LGR in this document has been adapted from the corresponding Reference LGR for the Second Level. The Second Level Reference LGR for the Ukrainian 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.
Adopted from the Second Level Reference LGR for the Ukrainian Language [Ref-LGR-uk-Cyrl] without normative changes.
General reference for the language:
Shevelov, George Y. 1993. “Ukrainian”, in Bernard Comrie & Greville G. Corbett, eds. The Slavonic languages. London; New York: Routledge. ISBN 0-415-04755-2
Other references cited in this document:
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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