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Second-Level Reference Label Generation Rules

ICANN has developed second-level Internationalized Domain Name (IDN) tables in machine-readable format or Label Generation Rules (LGRs) that registry operators can reference while designing their IDN tables. These reference LGRs will be used by ICANN org when reviewing IDN tables submitted for use with the generic top-level domains (gTLDs).

The reference LGRs have been developed using guidelines, which have been reviewed by the community. These LGRs are provided below in the XML format along with a more readable HTML format. See the Overview and Summary document for further details about these LGRs.

If you have questions or feedback regarding these reference LGRs, please send an email to IDNprogram@icann.org.

Name Language/Script Date Finalized LGR Documents Additional Information
Arabic Language 13 January 2021 HTML
XML
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Arabic Script 22 April 2021 HTML
XML
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Bangla (Bengali) Script 15 December 2020 HTML
XML
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Belarusian Language 19 December 2016 HTML
XML
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Bosnian (Cyrillic) Language 10 October 2016 HTML
XML
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Bosnian (Latin) Language 10 October 2016 HTML
XML
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Bulgarian Language 10 October 2016 HTML
XML
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Chinese Language 15 December 2020 HTML
XML

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The 10 October 2016 version HTML and XML.
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Danish Language 10 October 2016 HTML
XML
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Devanagari Script 15 December 2020 HTML
XML
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English Language 10 October 2016 HTML
XML
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Ethiopic Script 15 December 2020 HTML
XML
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Finnish Language 10 October 2016 HTML
XML
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French Language 10 October 2016 HTML
XML
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Georgian Script 15 December 2020 HTML
XML
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German Language 10 October 2016 HTML
XML
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Gujarati Script 15 December 2020 HTML
XML
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Gurmukhi Script 15 December 2020 HTML
XML
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Hebrew Language 22 April 2021 HTML
XML
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Hebrew Script 22 April 2021 HTML
XML
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Hindi Language 15 December 2020 HTML
XML
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Hungarian Language 10 October 2016 HTML
XML
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Icelandic Language 10 October 2016 HTML
XML
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Italian Language 10 October 2016 HTML
XML
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Kannada Script 15 December 2020 HTML
XML
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Khmer Script 15 December 2020 HTML
XML
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Korean Language 10 October 2016 HTML
XML
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Lao Script 22 April 2021 HTML
XML

Archive:
Version 1, 15 December 2020 (HTML, XML) View public comment materials.

Latvian Language 10 October 2016 HTML
XML
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Lithuanian Language 10 October 2016 HTML
XML
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Macedonian Language 10 October 2016 HTML
XML
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Malayalam Script 15 December 2020 HTML
XML
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Montenegrin Language 10 October 2016 HTML
XML
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Norwegian Language 10 October 2016 HTML
XML
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Oriya Script 15 December 2020 HTML
XML
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Polish Language 10 October 2016 HTML
XML
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Portuguese Language 10 October 2016 HTML
XML
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Russian Language 10 October 2016 HTML
XML
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Serbian Language 10 October 2016 HTML
XML
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Sinhala Script 22 April 2021 HTML
XML
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Spanish Language 10 October 2016 HTML
XML
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Swedish Language 10 October 2016 HTML
XML
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Tamil Script 15 December 2020 HTML
XML
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Telugu Script 15 December 2020 HTML
XML
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Thai Language 15 December 2020 HTML
XML
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Ukrainian Language 19 December 2016 HTML
XML
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Domain Name System
Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as""icann.org"" is not an IDN."