I'm not an accessibility expert, but I've been looking into some of these issues lately. A lot of this is just common sense and applies to all readers, not just those with what are commonly thought of as disabilities.
My understanding is that it is better to not have alternate text at all than it is to repeat the link text as alternate text. It's a little bit like the adage, "If you have nothing good to say, don't say anything at all." :-) All that is accomplished by putting in the text twice is forcing people to read it twice, which is more of a nuisance than a help.
I would argue that if the link text is the title of the target section, that is good enough. If the link text is a description, that is also good enough. Alternate text is useful only if you have a link that doesn't actually tell you what you're linking to (like "click here").
From: Bob Stayton [mailto:bobs@sagehill.net]
Sent: Friday, December 10, 2010 9:58 AM
To: redlettucemail; docbook-apps@lists.oasis-open.org
Subject: Re: [docbook-apps] Generating title for "link" element
Indeed, it is important. Currently a title attribute is automatically generated on the <a> element for a cross reference when the target element of the link has a title. The title attribute in the link is the title of the target.
I'm not clear that this customization to copy the link element's text into the title attribute should be the default behavior. It was my understanding that the title attribute was meant to add information about the target of the link. It would seem to me that copying the text of the link into the title attribute is not useful for that purpose. I mean, the text is present in the link element, and would be read by the screen reader. Duplicating that text in the title attribute would be redundant, wouldn't it?
I'm curious what others with experience in accessibility requirements think.
----- Original Message -----
Sent: Thursday, December 09, 2010 5:25 PM
Subject: Re: [docbook-apps] Generating title for "link" element
That worked beautifully thanks. That piece of code should be in the next release of the stylesheets, as a title attribute is important from an accessibility point of view.
Dave Gardiner