Malayalam

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

As part of the Root Zone, this LGR includes neither digits nor the HYPHEN-MINUS.

Code points outside the Malayalam 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 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 in-script variants and cross-script variants as described in Section 6, "Variants", in "[Proposal-Malayalam]". One in-script variant is due to the multiple ways to write the conjunct “nta" in Malayalam. Cross-script variants are mainly defined for Tamil code points.

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, the other one equivalent variant label should be blocked. There is no preference among these variants.

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

Context Rules for Variants: some of the variants defined in this LGR are "effective null variants", that is, some code points in the source map to "nothing" in the target with all other code points unchanged. (Because mappings are symmetric, it does not matter whether it is the forward or reverse mapping that maps to "null"). Such variants require a context rule to keep the variant set well-behaved. Symmetry requires the same context rule for both forward and reverse mappings.

In other cases, the sequences or code points making up source and target are constrained by context rules on the code points. In such a case, any variants require context rules that match the intersection between the contexts for both source and target; otherwise a sequence might be considered valid in some variant label when it would not be valid in an equivalent context in an original label.

Character Classes

The basic characters in Malayalam are classified here into the following categories: Consonants, Vowels, Matra and Reordrant Vowel Diacritics, Halant, Visargam, Anusvaram and Chillu letters.

Consonant: Malayalam is written in an abugida script derived ultimately from Brahmi in which every consonant carries an inherent /a/. More details in Section 3.8, "The Structure of Malayalam Script" of [Proposal-Malayalam].

Vowels: Like consonants, the independent vowels can follow any other class of code points in a label.

Matra: Vowels other than the inherent vowel are written as vowel diacritics. They are referred to as Matras, when they follow consonants. More details in Section 3.8, "The Structure of Malayalam Script" of [Proposal-Malayalam].

Halant: A consonant can be combined with another consonant or conjunct using the halant encoded as U+0D4D MALAYALAM SIGN VIRAMA. This strips off the implicit vowel. More details in Section 3.8, "The Structure of Malayalam Script" of [Proposal-Malayalam].

Anusvaram: In Malayalam, anusvara represented as U+0D02, simply represents a consonant /m/ after a vowel, though this /m/ may be assimilated to another nasal consonant. More details in Section 3.8, "The Structure of Malayalam Script" of [Proposal-Malayalam].

Visargam: The visarga represents a consonant /h/ after a vowel, and is transliterated as ḥ. Like the anusvara, it is a special symbol, and is never followed by an inherent vowel or another vowel. More details in Section 3.8, "The Structure of Malayalam Script" of [Proposal-Malayalam].

Chillu: Chillu letters, aka "Chillaksharam", represent pure consonants without any vowel sound. More details in Section 3.8, "The Structure of Malayalam Script" of [Proposal-Malayalam].

Reordrant: Vowel diacritics, part of which reorder around the preceding character or conjunct. More details in Sections 6.1 "In-script Variants" and 7.1.1 "Variables or definitions" of [Proposal-Malayalam].

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.

Malayalam-specific Rules

There are constraints on the context for many of the character classes in Malayalam. A corresponding set of context and whole label rules has been formulated for LGR specification, as described in Section 7, "Whole Label Evaluation (WLE) Rules" in [Proposal-Malayalam].

The following symbols are used in the WLE rules:
C → Consonant
M → Matra
V → Vowel
B → Anusvara
X → Visarga
D → Chandrabindu
H → Halant
L → Chillu
R → Reordrant Matra

Note: the Reordrant Matras include one sequence. That requires an auxiliary rule R in addition to class R.

The rules are:

• 1. H: must be preceded by C or U+0D41
• 2. M: must be preceded by C
• 3. B: must be preceded by C, V or M
• 4. X: must be preceded by C, V or M
• 5. L: cannot be preceded by B, X or H
• 6. A label does not begin with L

The following context rules apply to Consonants U+0D33 LLA and U+0D31 RRA as well as to sequences ending in these code points:

• 7. The character U+0D33 cannot immediately follow U+0D33, except as part of a defined sequence
• 8. The character U+0D31 cannot immediately follow U+0D31, except as part of a defined sequence

Note: the implementation of Rules 7 & 8 relies on the fact that a context rule is not evaluated between code points in the same sequence. For example, if a label contains two adjacent U+0D33 U+0D33 surrounded by other code points , the two code points can only be interpreted as the sequence U+0D33 U+0D33 because a singleton U+0D33 is not allowed to be followed by another U+0D33.

The following context rule applies to the sequence Chillu N + Halant (U+0D7B U+0D4D):

• 9. The sequence U+0D7B U+0D4D must be preceded by C, L, M, V and must be followed by U+0D31

The following context rules apply to variants:

• V1: A variant is defined when followed by U+0D31
• V2: A variant preceded by 0D33+Halant or followed by R or Halant+0D33 is not defined
• V3: A variant preceded by 0D31+Halant or followed by R or Halant+0D31 is not defined

These rules ensure that the variant label sets are well-behaved in cases where variant sequences overlap.

Note: any sequences ending with 0D31 would overlap with the various variant sequences beginning with 0D31, therefore this LGR drops the 0D31 from the end of these sequences, but adds context rule V1, when="followed-by-0D31" instead. Because all the variants also end in 0D31, this results in the same generated variants as if the sequences had been defined with trailing U+0D31, but now the variants are well-behaved in all contexts.

More details in Section 6.1, "In-script Variants" and Section 7, "Whole Label Evaluation Rules (WLE)" of [Proposal-Malayalam]

There are a number of cross-script homoglyphs to U+0D31 RRA, which would interact with the definition of in-script sequences and variants, leading to unacceptable complexity. These variants would affect only labels made solely of letters RRA, and no other labels. Rule 8 already restricts labels consisting solely of copies of the letter RRA to either "റ" or "ററ", thus allowing only two such labels. The following rule disallows the remaining two possible labels, obviating any need to define these cross-script variants.

• 10. A label cannot consist solely of letters U+0D31 RRA

Malayalam-specific actions

WLE rules 6 and 10 trigger Malayalam-specific actions to invalidate any original and variant labels not satisfying the constraints. See Section 7, "Whole Label Evaluation (WLE) Rules" in [Proposal-Malayalam].

Methodology and Contributors

The Root Zone LGR for the Malayalam 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 in [Proposal-Malayalam], as well as [RZ-LGR-4-Overview].

Changes from LGR-3

This LGR has been updated for LGR-4 to address an inconsistency involving the conjunct "nta" and to eliminate some potentially complex interactions with cross script variants. For the prior version see [RZ-LGR-3-Mlym].

1. Removed Chillu N from rule 1 and added a new context rule applied to the sequence Chillu N + Halant (U+0D7B U+0D4D):

   • 9. The sequence U+0D7B U+0D4D must be preceded by C, L, M, V and must be followed by U+0D31

   This change disallows some contexts that should not have been allowed for U+0D4D when following U+0D7B.

2. Added a new context rule applied to variants:

   • V1: A variant is defined when followed by U+0D31

   The definition of the sequences to which this context rule applies has been changed by dropping the final U+0D31. This is an equivalent formulation. The change simplifies the formulation of other rules and variant definitions.

3. Added a new whole-label rule (and corresponding action):

   • 10. A label cannot consist solely of letters U+0D31 RRA

   This rule invalidates the two labels U+0D31 and U+0D31 U+0D31, obviating the need to define certain cross-script variants for U+0D31

Note: as result of the update, the LGR is slightly more restrictive.

References

The following general references are cited in this document:

[MSR-4]

Integration Panel, "Maximal Starting Repertoire — MSR-4 Overview and Rationale", 7 February 2018, https://www.icann.org/en/system/files/files/msr-4-overview-25jan19-en.pdf

[Proposal-Malayalam]

Neo-Brahmi Generation Panel, "Proposal for a Malayalam Script Root Zone Label Generation Ruleset (LGR)", Updated 26 June 2020, https://www.icann.org/en/system/files/files/proposal-malayalam-lgr-26jun20-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

[RZ-LGR-Overview]

Integration Panel, "Root Zone Label Generation Rules - LGR-4: Overview and Summary", 01 March 2020 (PDF), https://www.icann.org/sites/default/files/lgr/lgr-4-overview-10jul19-en.pdf

[RZ-LGR-4]

Integration Panel, "Label Generation Rules for the Root Zone — LGR-4", 05 November 2020 (XML), https://www.icann.org/sites/default/files/lgr/lgr-4-common-05nov20-en.xml
non-normative HTML presentation: https://www.icann.org/sites/default/files/lgr/lgr-4-common-05nov20-en.html

[RZ-LGR-3-Mlym]

ICANN, Root Zone Label Generation Rules for the Malayalam Script (und-Mlym), Version 3, 10 July 2019 (XML) https://www.icann.org/sites/default/files/lgr/lgr-3-malayalam-script-10jul19-en.xml

[RZ-LGR-4-Overview]

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

[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 Malayalam script for the Root Zone please see details in the Table of References below. References [0] to [9] refer to the Unicode Standard versions in which the corresponding code points were initially encoded. Reference [106] corresponds to a source given in [Proposal-Malayalam] justifying the inclusion of the corresponding code points. Entries in the table may have multiple source reference values.