agenda+ Fwd: Ruby accessibility gap in WCAG and upcoming proposal for WCAG 2.3

Thank you, Makoto-san. Adding to our agenda.



-------- Forwarded Message --------
Subject:  Ruby accessibility gap in WCAG and upcoming proposal for WCAG 2.3
Resent-Date:  Tue, 04 Nov 2025 23:06:30 +0000
Resent-From:  public-i18n-core@w3.org
Date:  Wed, 5 Nov 2025 07:15:43 +0900
From:  村田真 <founder@info-a11y.jp>
To:  Internationalization Working Group <public-i18n-core@w3.org>



Dear I18N WG colleagues,

In yesterday’s AG WG call, I realized something that I had not fully 
appreciated before: PDF documents are fully within scope for WCAG.  
Given that, I want to raise an issue that is both technical and 
architectural, and is highly relevant to our group’s charter.

As you know, Japanese, Chinese, and some other writing systems require 
ruby annotations to convey reading information that is essential for 
comprehension.
However, WCAG currently includes no success criterion that ensures that 
the relationship between base text and ruby annotations is preserved.

In HTML, this relationship is generally preserved through the ruby 
markup model.  But in PDF, ruby is often represented as a separate line 
of text, resulting in a complete loss of semantic association, making 
the document effectively unreadable for users relying on assistive 
technologies.

Meanwhile, ISO 32000-2 (PDF 2.0) defines a correct ruby annotation 
structure, and PDF/UA includes guidance aligned with it.  I l 
learned from somebody in Adobe that their implementations fully support 
such correct structures..  So the missing piece is not technical 
capability, but rather the absence of a requirement in WCAG that would 
ensure this association must be preserved.

I intend to propose a new success criterion in WCAG 2.3 requiring that 
content preserve the explicit parent–ruby relationship in a way that 
allows user agents and assistive technologies to:

  * hide or show ruby,
  * adjust visual presentation (size, spacing, color), and
  * convey the association programmatically for TTS.

Before drafting concrete wording, I plan to explain the rationale and 
show a short example in our call this Friday.
After that, I will prepare a proposal text, and I would appreciate the 
Working Group’s feedback before submitting it to AG WG.

I believe this can be a constructive and important contribution from 
I18N WG to WCAG 2.3, addressing a longstanding architectural gap.

Best regards,
Makoto