Lao

Each code point is tagged with the script or scripts with which the code point is used, one or more other character categories, and one or more references documenting sufficient justification for inclusion in the repertoire; see “References” below. Comments identify the language using the code point.

Variants

According to Section 6, “Variants” in [Proposal-Lao], this LGR defines no variants.

Character Classes

Consonants: In regular syllables, consonants occur in limited combinations. However, arbitrary combinations are used for acronyms. The LGR therefore considers the restriction on syllabic combinations a matter of spelling and does not enforce them. Consonants may be followed by a semi-consonant mark. Some consonants have been given the tag “Cf”, which indicates final consonants. See Section 5, “Consonants” in [Proposal-Lao].

Vowels: Vowels are divided into vowel-above, vowel-before, vowel-below and vowel-after so as to enforce some of the syllable structure using context rules. However, many details have been considered spelling issues and, for simplification, are not modeled in this LGR. See Section 5 in [Proposal-Lao].

Semi-consonant: The character U+0EBC LAO SEMIVOWEL SIGN LO follows consonants (see Section 5 in [Proposal-Lao]).

Tone-mark: Any of four tone marks can follow a consonant or vowel-above or vowel-below (see Section 5 in [Proposal-Lao]).

Signs: The character U+0ECC LAO CANCELLATION MARK follows a final consonant (Cf). The character U+0EC6 (ໆ) LAO KO LA is a repetition mark that can only occur up to 3 times at the end of the label (See Section 5 in [Proposal-Lao]).

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-5]. 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-before.

Lao-specific Rules

Rules provided in the LGR as described in Section 7 of [Proposal-Lao] reasonably restrict labels so that they conform to Lao syllable structure. These constraints are presented exclusively as context rules.

The rules are:

• follows-consonant — A context rule for semi-consonant. See Section 7 in [Proposal-Lao]. (WLE Rule 1)
• precedes-consonant — A context rule for vowel-before. See Section 7 in [Proposal-Lao]. (WLE Rule 2)
• follows-main-consonant — A context rule for vowel-below, and vowel-above. See Section 7 in [Proposal-Lao]. (WLE Rule 3)
• follows-C-tonemark-vabove — A context rule for vowel-after. See Section 7 in [Proposal-Lao]. (WLE Rule 4)
• follows-vbefore-consonant-cluster — A context rule for a vowel-after sequence. It incorporates consonant-cluster. See Section 7 in [Proposal-Lao]. (WLE Rule 5)
• follows-C-vabove-vbelow — A context rule for tone mark. See Section 7 in [Proposal-Lao]. (WLE Rule 6)
• follows-Cf — A context rule for U+0ECC (໌ ) LAO CANCELLATION MARK. See Section 7 in [Proposal-Lao]. (WLE Rule 7)
• repetition-mark-limit — A rule that limits the occurrence of U+0EC6 ( ໆ ) LAO KO LA at the label end. See Section 7 in [Proposal-Lao]. (WLE Rule 8)

No context rules apply to “consonant” code points. For discussion, see Section 5.1, “Consonants” in [Proposal-Lao].

Methodology and Contributors

The Root Zone LGR for the Lao script was developed by the Lao Generation Panel. For methodology and contributors, see Sections 4 and 8 in [Proposal-Lao], as well as [RZ-LGR-5-Overview].

References

The following general references are cited in this document:

[MSR-5]

Integration Panel, “Maximal Starting Repertoire — MSR-5 Overview and Rationale”, 24 June 2021, https://www.icann.org/en/system/files/files/msr-5-overview-24jun21-en.pdf

[Proposal-Lao]

Lao Generation Panel, “Proposal for Lao Script Root Zone LGR”, Version 3.1, https://www.icann.org/en/system/files/files/proposal-lao-lgr-31jan17-en.pdf

[RFC 7940]

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

[RZ-LGR-5-Overview]

Integration Panel, “Root Zone Label Generation Rules (RZ LGR-5): Overview and Summary”, 26 May 2022, https://www.icann.org/sites/default/files/lgr/rz-lgr-5-overview-26may22-en.pdf

[RZ-LGR-5]

Integration Panel, “Root Zone Label Generation Rules (RZ-LGR-5)”, 26 May 2022 (XML), https://www.icann.org/sites/default/files/lgr/rz-lgr-5-common-26may22-en.xml
non-normative HTML presentation: https://www.icann.org/sites/default/files/lgr/rz-lgr-5-common-26may22-en.html

[Unicode 11.0]

The Unicode Consortium. The Unicode Standard, Version 11.0.0, (Mountain View, CA: The Unicode Consortium, 2018. ISBN 978-1-936213-19-1) https://www.unicode.org/versions/Unicode11.0.0/

For references consulted particularly in designing the repertoire for the Lao script for the Root Zone please see details in the Table of References below. Reference [0] refers to the Unicode Standard version in which corresponding code points were initially encoded. References [201], [202], [203], [204], 205], [206], & [207] correspond to sources given in [Proposal-Lao] justifying the inclusion of or classification for the corresponding code points. Entries in the table may have multiple source reference values.