Root Zone Label Generation Rules for the Telugu Script

Overview

This file contains Label Generation Rules (LGR) for the Telugu script for the Root Zone. For more details on this LGR and its development, see "Proposal for a Telugu Script Root Zone Label Generation Ruleset (LGR)" [Proposal]. The format of this file follows [RFC 7940].

Repertoire

According to Section 5, "Repertoire" in [Proposal], the Telugu LGR contains 63 unique code points. This LGR primarily caters to the Telugu language written using the Telugu script. Several other languages with [EGIDS] levels above 4 were also considered in the analysis.

The repertoire is based on [MSR-4], which is a subset of [Unicode 6.3].

Code points outside the Telugu script that are listed in this file are targets for out-of-script variants and are identified by a reflexive (identity) variant of type "out-of-repertoire-var". They do not form part of the repertoire.

Each code point is tagged with the script or scripts that the code point is used with, a category value, and one or more references documenting sufficient justification for inclusion in the repertoire, see "References" below. Comments provide alternate names for some code points.

Variants

According to Section 6, "Variants", in [Proposal], this LGR defines cross-script variants which are "Confusing due to deviation from normally perceived character formations by larger linguistic community". These cases are not of mere visual similarity; they can cause confusion even to a careful observer and hence have been defined as variants. There are no in-script variants defined for Telugu.<

Variant Disposition: All variants are of type "blocked", making labels that differ only by these variants mutually exclusive: whichever label containing either of these variants is chosen earlier would be delegated any other equivalent label should be blocked. There is no preference among these variants.

This LGR does not define allocatable variants.

The specification of variants in the Root Zone LGR follows the guidelines in [RFC 8228].

Character Classes

The Telugu orthography superficially resembles a series of circles and semi-circles. Most consonants carry a tick mark called ‘talakattu’. The writing system is classified as abugida type or alpha-syllabary The alphabet consists of vowels, consonants and modifiers. Each of these vowels and consonants have one or more secondary allographs.

Consonants: The Telugu consonants contain an implicit vowel /a/ . More details in Section 3.5.4, "The Consonants" of the [Proposal].

Vowels and dependent vowel signs: There are fourteen vowel characters in the common inventory of which one is rarely used U+0C0C (ఌ). It and the two obsolete vowels (ౠ, ౡ) are excluded from this LGR. Each vowel, except U+0C05 (అ) has a dependent vowel sign, modifying the vowel of the consonant they follwo. These signs mayhave different appearance depending on the size and shape of the consonant that functions as an anchor. More details in Section 3.5.1, "The vowels and vowel modifiers" of the [Proposal].

Anusvara or sunna: The Anusvara or sunna represents a homorganic nasal before the corresponding consonant and as a substitute to transcribe word final /mu/. Essentially, it substitutes a cluster of a Nasal Consonant+Halant before a consonant. More details in Section 3.5.2, "The Anusvara or sunna" of the [Proposal].

Visarga: Visarga denotes the glottal check.

Halant: A special sign is needed whenever the implicit vowel in the preceding consonant is stripped off. This symbol is known as the Halant. (Any vowel sign will also deduct the implicit vowel). More details in Section 3.5.1, "The vowels and vowel modifiers" of the [Proposal].

Whole Label Evaluation (WLE) and Context Rules

Default Whole Label Evaluation Rules and Actions

The LGR includes the set of required default WLE rules and actions applicable to the Root Zone and defined in [MSR-4]. They are marked with ⍟. The default prohibition on leading combining marks is equivalent to ensuring that a label only starts with a consonant or vowel.

Telugu-specific Rules

These rules have been formulated so that they can be adopted for LGR specification.

The following symbols are used in the WLE rules:
C → Consonant
M → Matra (Dependent vowel signs)
V → Vowel
B → Anusvara (Bindu)
X → Visarga
H → Halant / Virama
Nasal-C → Nasal Consonant

The rules are:

• 1. H: must be preceded by C
• 2. M: must be preceded by C
• 3. X: must be preceded by V, M or C
• 4. B: must be preceded by V, M or C
• 5. H: cannot follow Nasal-C
• 6. V: cannot be preceded by H

More details in Section 7 "Whole Label Evaluation Rules (WLE)" of the [Proposal].

Methodology and Contributors

The LGR for the Telugu script was developed by the Neo-Brahmi Generation Panel (NBGP) the members of which have experience in linguistics and computational linguistics in a wide variety of languages written with Neo-Brahmi scripts. Under the Neo-Brahmi Generation Panel, there are nine scripts belonging to separate Unicode blocks. Each of these scripts has been assigned a separate LGR, with the Neo-Brahmi GP ensuring that the fundamental philosophy behind building each LGR is in sync with all other Brahmi derived scripts. For further details on methodology and contributors, see Sections 4 and 8 of [Proposal].

References

The following general references are cited in this document:

[EGIDS]

Expanded Graded Intergenerational Disruption Scale,
https://www.ethnologue.com/about/language-status
(Accessed on 13 Nov. 2017)

[MSR-4]

Integration Panel, "Maximal Starting Repertoire — MSR-4 Overview and Rationale", 7 February 2019,
https://www.icann.org/en/system/files/files/msr-4-overview-25jan19-en.pdf

[Proposal]

Neo-Brahmi Generation Panel, “Proposal for a Telugu Script Root Zone Label Generation Ruleset (LGR)”, 6 March 2019,
https://www.icann.org/en/system/files/files/proposal-telugu-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.

[RFC 8228]

A. Freytag, "Guidance on Designing Label Generation Rulesets (LGRs) Supporting Variant Labels", RFC 8228, August 2017,
https://www.rfc-editor.org/info/rfc8228

[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/

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.