The language of parts and assistive technology pronunciation issues

1 February 2018 | Ted Page

Marking up changes in natural language appropriately is a WCAG 2.0, level AA, requirement (SC 3.1.2). Specifically, SC 3.1.2 states:

The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text.

Video: PDF accessibility and the language of parts

The following video demonstrates the importance of correctly tagging language changes in a PDF, as well as how to do so in Microsoft Word, InDesign and Acrobat Pro.

Transcript: PDF accessibility and the language of parts (accessible PDF, 122KB)

Mange tout Rodney

Clearly, getting this right is important if the example in the video, or worse, is to be avoided (<alert class="uk_specific_cultural_reference">Mange tout Rodney</alert>).


However, it is also important to note the exceptions listed in SC 3.1.2, such as proper names, technical terms and unassimilated words or phrases, and the problems that these might present. 

For example, take the name John von Neumann (mathematician and game theoretician). In English language documents, most of the major assistive technologies, including JAWS, NVDA, VoiceOver, ZoomText Reader, Read&Write Gold and ClaroRead, pronounce “Neuman” as “Newman” (SuperNova and C-Pen Reader get it more or less right). But marking it up as German (in the context of an English language document) also sounds wrong. The same will go for place names. Try, for example, Antony (Île-de-France) or Bremerhaven.

Cue: pronunciation style sheets 

Marking up language attributes is insufficient to solve all pronunciation problems. The solution to these exceptions, as well as to many other pronunciation problems lies in the adoption of pronunciation style sheets: PLS (Pronunciation Lexicon Specification) and SSML (Synthetic Speech Markup Language). 

For when it really matters

Correcting pronunciation problems is a Level AAA WCAG 2.o requirement (SC 3.1.6), and as such may be a little off the radar for many. However, the early adoption of these technologies for both PDF and EPUB formats would be most welcome, especially for those working with educational documentation (particularly exam papers), technical materials, or perhaps medical literature or instructions, where clarity and ease of use are paramount, and where misunderstandings may have serious consequences.

Afterword: JAWS 2018 bug

At the time that the above video was recorded there was a bug in the current version of JAWS (version 2018) preventing it from correctly reading language attributes in a PDF (other than alt text and link text). Hence the video was recorded using JAWS 18 (the previous version). The JAWS 2018 bug has been reported to Freedom Scientific and hopefully will soon be fixed.