Reference Label Generation Rules for the Gujarati Script

Overview

This document specifies a reference set of Label Generation Rules (LGR) for the Gujarati script for the second level. The starting point for the development of this LGR can be found in the related Root Zone LGR [RZ-LGR-4-Gujr]. For details and additional background on the script, see "Proposal for a Gujarati Script Label Generation Ruleset for the Root Zone" [Proposal-Gujarati]. The format of this file follows [RFC 7940].

Repertoire

This LGR contains 65 code points for letters covering multiple languages written using the Gujarati script and ranging from 1 to 4 on the [EGIDS] scale. The repertoire is a subset of [Unicode 6.3]. For more detail, see Section 5, "Repertoire" in [Proposal-Gujarati]. (The proposal cited has been adopted for the Gujarati script portion of the Root Zone LGR.)

For the second level, the repertoire has been augmented with the Gujarati digits, U+0AR6 to U+0AEF (૯), ASCII digits U+0030 (0) to U+0039 (9), and U+002D (-) HYPHEN-MINUS for a total of 86 repertoire elements.

Each code point or range is tagged with the script or scripts that the code point is used with, one or more tag values denoting character category, and one or more references documenting sufficient justification for inclusion in the repertoire, see "References" below.

Variants

This LGR defines no variants for letters. For details, see Section 6, "Variants" in [Proposal-Gujarati].

Digit Variants: All Gujarati digits are treated as semantic variants of the corresponding common (ASCII) digits. By transitivity, they are also semantic variants of any native digits in scripts that also include the common digits. Such variant relations are deemed to exist implicitly by transitivity but are not listed explicitly in each reference LGR. (Omitting the listing of these other cross script digit variants does not affect index variant calculation, as the ASCII digit variant being smallest would always be the index variant.) Note that in addition to a transitive semantic variant relation, Gujarati digits ZERO, TWO, FOUR, and EIGHT are cross-script homoglyphs or near homoglyphs with Devanagari digits of the same value. Digit FOUR is also a variant of Oriya digit FOUR. Gujarati digit ZERO is a cross-script homoglyph or near homoglyph of digit ZERO in many other scripts; these are already implicit semantic variants by transitivity and therefore not listed here.

Some Gujarati letters share forms with digits: U+0AB0 (ર) GUJARATI LETTER RA is a homoglyph variant of U+0aE8 (૨) GUJARATI DIGIT TWO. U+0AAA (પ) GUJARATI LETTER PA is a homoglyph variant of U+0AEB (૫) GUJARATI DIGIT FIVE. By transitivity, the ASCII digits TWO and FIVE are also variants of the respective letters, and so are all other corresponding native digits TWO and FIVE, even though not explicitly listed here.

To keep digit variant sets manageable in zones where multiple scripts are present, no attempt has been made at identifying cross-script variants among digits of different numeric value, such as between Gujarati digit ONE and Bengali digit SEVEN; or between a digit in one script and a letter in another, such as between digit zero and Latin letter 'o'.

Character Classes

Gujarati is an alphasyllabary and the heart of the writing system is the akshar. This is the unit which is instinctively recognized by users of the script. As encoded, the writing system of Gujarati is composed of Consonants, the Implicit Vowel Killer: Halant, Vowels, Anusvara, Candrabindu, Nukta, Visarga and Avagraha.

Consonants: Gujarati consonants contain an implicit vowel schwa /ə/. The traditional classification categorizes them according to their phonetic properties. There are 5 Varga groups (classes) and one non-Varga group. Each varga, which corresponds to a particular stop, contains five consonants classified as per their properties. The first four consonants are classified on the basis of Voicing and Aspiration and the last is the corresponding nasal. More details in Section 3.4.1, "The Consonants" of the [Proposal-Gujarati].

Halant: All consonants contain the implicit vowel (schwa). A special sign is needed to denote that this implicit vowel is stripped off. This is known as the Halant (્). The Halant thus joins two consonants and creates conjuncts, which generally combine 2 to 4 consonants. In rare cases the Halant can join up to 5 consonants. More details in Section 3.4.2, "The Implicit Vowel Killer: Halant" in [Proposal-Gujarati].

Vowels and Matras: Separate symbols exist for all Vowels, which are either pronounced independently at the beginning or attached to a consonant. To indicate the latter (other than the implicit one), a Vowel modifier (matra) is attached to the consonant. Since the consonant has a built-in schwa, there are equivalent Matras for all vowels excepting the અ (U+0A85). More details in Section 3.4.3, "Vowels" in [Proposal-Gujarati].

Anusvara: In Gujarati, the Anusvara has a dual function. On the one hand, it acts as homorganic nasal, that is, it replaces a conjunct group of a Nasal Consonant+Halant+Consonant belonging to that particular varga. On the other hand, before a non-varga consonant the anusvara represents a nasal sound. Gujarati and its dialects prefer the anusvara to the corresponding half-nasal. More details in Section 3.4.4, "The Anusvara" in [Proposal-Gujarati].

Nukta: Traditionally Gujarati does not admit the Nukta. Gujarati grammarians in their inventory of the Gujarati alphabet do not admit this diacritic. However, the Nukta is used to represent content where Perso-Arabic characters have to be transliterated. It follows specific consonants listed in set C1. More details in Section 3.4.6, "Nukta" in [Proposal-Gujarati].

Visarga and Avagraha: The Visarga is frequently used in Sanskrit and represents a sound very close to /h/, as in દુઃખ /du:kh/ sorrow, unhappiness. It is used sparingly in Gujarati with a few words borrowed from Sanskrit. The Avagraha is rarely used and excluded from the LGR. More details in Section 3.4.7, "Visarga and Avagraha" in [Proposal-Gujarati].

Common Digits: U+0030 (0) to U+0039 (9) are the set of digits from the ASCII range.

Gujarati Digits: U+0AE6 (૦) to U+0AEF (૯) are a set of Gujarati-specific digits.

Whole Label Evaluation (WLE) and Context Rules

Common Rules

• 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 RFC 5891 [150]. 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 RFC 5891 [150].
• Digit-mixing — no mixing between different digit sets (European and Gujarati digits) is allowed; implemented here as a WLE rule with associated action.

Default Actions

Actions include the default actions for LGRs as well as that needed to invalidate labels with misplaced combining marks. They are marked with ⍟. For a description see [RFC 7940].

Gujarati-specific Rules

These rules have been drafted to ensure that the prospective Gujarati label conforms to akshar formation norms as desired in Gujarati script. These norms are exclusively presented as context rules.

The following symbols are used in the WLE rules:
C → Consonant
M → Matra
V → Vowel
B → Anusvara
X → Visarga
H → Halant/Virama
N → Nukta
C1 → Consonants used with Nukta

The rules are:

• 1. N: must be preceded by any of the specific set of Consonants (C1)
• 2. H: must be preceded either by C or N
• 3. X: must be preceded by any of V, C, N or M
• 4. B: must be preceded by any of V, C, N or M
• 5. M: must be preceded either by C or N

More details in Section 7,"Whole Label Evaluation Rules (WLE)" in [Proposal-Gujarati].

Methodology and Contributors

This reference LGR for the Gujarati script for the 2nd Level has been developed by Michel Suignard and Asmus Freytag, based on the Root Zone LGR for Gujarati and information contained or referenced therein, see [RZ-LGR-4-Gujr]. Suitable extensions for the second level have been applied according to the [Guidelines]. The original proposal for a Root Zone LGR for the Gujarati script, that this reference LGR is based on, was developed by the Neo-Brahmi Generation Panel (NBGP). For more information on methodology and contributors to the underlying Root Zone LGR, see Sections 4 and 8 in [Proposal-Gujarati], as well as [RZ-LGR-Overview].

References

The following general references are cited in this document:

[Guidelines]

ICANN, "Guidelines for Developing Reference LGRs for the Second Level, (Los Angeles, California: ICANN, 27 May 2020),
https://www.icann.org/en/system/files/files/lgr-guidelines-second-level-06jan16-en.pdf

[EGIDS]

Expanded Graded Intergenerational Disruption Scale,
https://www.ethnologue.com/about/language-status

[Proposal-Gujarati]

Neo-Brahmi Generation Panel, "Proposal for a Gujarati Script Root Zone Label Generation Ruleset (LGR)", 6 March 2019,
https://www.icann.org/en/system/files/files/proposal-gujarati-lgr-06mar19-en.pdf

[RFC 7940]

Davies, K. and A. Freytag, "Representing Label Generation Rulesets Using XML", RFC 7940, August 2016,
http://www.rfc-editor.org/info/rfc7940

[RZ-LGR-Overview]

Integration Panel, "Root Zone Label Generation Rules - LGR-4: Overview and Summary", 5 November 2020 (PDF),
https://www.icann.org/sites/default/files/lgr/lgr-4-overview-05nov20-en.pdf

[RZ-LGR-4-Gujr]

ICANN, Root Zone Label Generation Rules for the Gujarati Script (und-Gujr) , 5 November 2020 (XML)
https://www.icann.org/sites/default/files/lgr/lgr-4-gujarati-script-05nov20-en.xml

[Unicode 6.3]

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/

For references consulted particularly in designing the repertoire for the Gujarati script for the second level please see details in the Table of References below. Reference [0] refers to the Unicode Standard version in which the corresponding code points were initially encoded. Reference [101] corresponds to a source justifying the inclusion of the corresponding code points. Entries in the table may have multiple source reference values. Reference [150] indicates the source for common rules.

4.1 Character Classes

The following table lists all named and implicit classes with their definition and a list of their members intersected with the current repertoire (for larger classes, this list is elided).

4.2 Whole label evaluation and context rules

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 or variant.

4.3 Actions

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.