What are appropriate markup languages for users with disabilities?

Suppose you're developing a web site and blind users will be a significant chunk of your target market. If the web site includes document editing functionality, what would be appropriate WYSIWYM tools? Are languages like Markdown, Textile and Wiki Formatting really accessible or are they inconvenient to bl开发者_StackOverflow中文版ind users?

I'm a blind programmer and while I haven't used most of the languages you mention I've found that any markdown language is fairly easy to use if you have the desire to learn it. I've had no problem using either HTML or several markup languages for wiki's. Part of it will depend on how invested the users are in your site. If it's a site that will be visited infrequently or for short periods of time, it's much less likely that a user will take the time to learn the required markup whether they are blind or not. Unfortunately, I have not found an accessible JavaScript WYSIWYG editor but I find it easier to manually enter the markup so haven't looked very hard.

the first question is: how important is semantic structure? could you get away with plain text. You could do simple parsing like treating blank lines as paragraph markers, treating a series of lines which begin with * as a bulleted list, identify URLs and make them into links, etc.

As a blind developer myself, I have no problem in understanding languages like Markdown. But if it's a syntax I'm unfamiliar with, I'll only learn it if I expect to use the site very often, or care deeply about the content.

Two final thoughts come to mind: while I certainly experience some accessibility challenges using TinyMCE, you could develop something much simpler - provide less than 10 formatting options, like inserting hyperlinks, making lists, centering text, setting the style (such as heading) etc.

And lastly, when I talk to non-technical blind people, they often just write their content in Word and paste into a wiki or blog post. This sounded strange when I first heard it, but it does make sense. So an ideal solution would accept pasted in content.

In closing - it depends how important this is, and how much effort you want to expend. Maybe a Markdown editor with a live preview (like on this site), buttons for inserting simple formatting like URLs, and the ability to paste in rich text would tick all boxes :-)

On a web page, the most accessible embedded text editor for blind users is one that uses standard HTML, such as a <textarea> element, with a corresponding <label> element:

<label for="editor">Enter your text here using wiki markup:</label>
<textarea id="editor"></textarea>

If a WYSIWYM tool is built using standard accessible HTML, then blind users can easily enter text into it, with full confidence that they're entering text in the right place. Then the question becomes: Which is the better markup language? They all require memorization, but some may be more intuitive than others. One way to find out which is best would be to do some usability testing with a wide variety of target users. Also be sure to providing easy, accessible access to syntax help.

Picture yourself working in pure text 80x4 display (just open a console and resize appropriately), then use vi/emacs/ed and you'll soon realize what markup will get in the way.

Try to do as much work as possible to understand plain text, else use light markup like POD, finally things like AsciiDoc are very powerful but needs training.

I don't know about WYSIWYG/WYSIWYM tools, but I do know that complying with W3C standards (especially their HTML5 en CSS3 drafts) while writing your own editor code will help a lot.

In CSS you can specify speed and intonation of speech. In HTML you can specify alternative text (alt attribute in many elements) that screen readers are compatible with. Be sure to know when to use the abbr and the acronym elements. Use the former when you want the screen reader to read the meaning of an abbreviation and the latter when the acronym should be read as a word (e.g. ASAP, NATO and OS).

For the editor itself, I recommend creating a WYSIWYG editor that uses divs and spans. Screen readers will understand easily the structure of a document. For the current line, use a text box; for every other line that's not being edited, convert the contents immediately to valid HTML.

If you find a good tool, be sure to post it here. I'm looking for one too. :-)