This document points to resources for the layout and presentation of text in languages that use the Lao script. The target audience includes developers of Web standards and technologies, such as HTML, CSS, Mobile Web, Digital Publications, and Unicode, as well as implementers of web browsers, ebook readers, and other applications that need to render Lao text.
This document points to resources for Lao script layout and text support on the Web and in eBooks. These requirements provide information for Web technologies such as CSS, HTML and digital publications about how to support languages written using the Lao script. The information here is developed in conjunction with a document that summarises gaps where the Web fails to adequately support the Lao script.
The editor's draft of this document is being developed in the GitHub repository Southeast Asian (sealreq), with contributors from the W3C Internationalization Interest Group. It is published by the Internationalization Working Group. The end target for this document is a Working Group Note.
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This document was created by Richard Ishida.
The following people contributed information that was used in preparing this document (in alphabetic order): Anousak Anthony Souphavanh, Arthit Suriyawongkul, Ben Mitchell, James Clarke, John Durdin, Martin Hosken, and Norbert Lindenberg as members of the W3C's Southeast Asian Language Enablement community.
See also the GitHub contributors list for the Southeast Asian Language Enablement project, and the discussions related to the Lao script.
This document points to resources for Lao script layout and text support on the Web and in eBooks. These resources provide information for developers of Web technologies such as CSS, HTML and digital publications, and for application developers, about how to support languages written using the Lao script. They include requirements, tests, GitHub discussions, type samples, and more,
The document focuses on typographic layout issues. For a deeper understanding of the Lao script and how it works see Southeast Asian Orthography Notes, which includes topics such as: Phonology, Vowels, Consonants, Encoding choices, and Numbers.
This document should be used alongside a separate document, Lao Gap Analysis, which describes gaps in language support for users of the Lao script, and prioritises and describes the impact of those gaps on the user.
Gap reports are brought to the attention of spec and browser implementers, and are tracked via the Gap Analysis Pipeline. (Filter for Lao script items)
The document Language enablement index points to this document and others, and provides a central location for developers and implementers to find information related to various scripts.
The W3C also has a repository with discussion threads related to the Lao script, including requests from developers to the user community for information about how scripts/languages work, and a notification system that tracks issues in W3C working groups related to the Lao script. See a list of unresolved questions for Lao experts. Each section below points to related discussions. See also the repository home page.
The Lao orthography is an alphabet. This means that both consonants and vowels are indicated.
Lao text runs left to right in horizontal lines. Spaces separate phrases, rather than words. There is no case distinction.
Each onset consonant is associated with a high, mid, or low class related to tone. Tone is indicated by a combination of the consonant class, the syllable type (live/dead), plus any tone mark.
No conjuncts are used for consonant clusters, except for one subjoined consonant, used in combination only with HA.
Syllable-initial clusters and syllable-final consonant sounds are all written with ordinary consonant letters. However, because all vowels are written, it is not difficult to algorithmically detect syllable boundaries.
Unlike its close relative, Thai, the Lao orthography is an alphabet and has no inherent vowel, but it still represents vowels using vowel signs (including combining marks, dedicated vowel letters, and a couple of repurposed consonants).
Vowels in Lao are written with a mixture of combining characters and ordinary spacing characters. Lao uses visual placement: only the vowel components that appear above or below the consonant are combining marks; the others are ordinary spacing characters that are typed in the order seen. There are pre-base vowel glyphs. In principle, there are no single-character circumgraphs in Lao text, but a single vowel or diphthong is frequently made up of multiple components.
There are no independent vowels, and standalone vowel sounds are written using vowel signs applied to ອ U+0EAD LETTER O.
Lao has a large number of multipart vowels (including diphthongs) made from dedicated vowel characters and from consonants. Composite vowels can involve up to 4 glyphs (plus a tone mark), and glyphs can surround the base consonant(s) on up to 3 sides.
Vowels are often written differently when they appear in a closed vs. open syllable.
Lao has native digits, and they are commonly used.
Lao is written horizontally, left to right.
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