Unicode Explained

Section 508 legislation makes accessibility considerations mandatory in some contexts

that involve federal funding, see http://www.section508.gov/.

Characters in non-visual presentation

The most commonly presented example of accessibility is how to make web pages and

other digital content available to the blind. Tools used for this usually involve speech

synthesis: textual content is used as input to an automatic speech synthesizer, which

reads the text audibly. The synthesizer may use metainformation presented in markup,

for example, in order to read headings emphatically and to leave pauses between para-

graphs. Alternatively, text could be presented via a Braille “display,” which is a device

that renders a character using a combination of dots (a Braille pattern) that can be

sensed by the user’s fingertips.

These examples deal with a very narrow part of accessibility, but they illustrate well

how accessibility deals with the character level, too. Unicode is oriented toward char-

acters that are displayed visibly. The very character concept deals with elements of

written text, even though it does not mandate a particular presentation. Strings of Uni-

code characters can, however, be presented in other ways, too.

Speech synthesis needs much more than just characters. It must be strongly language-

dependent to be correct or even to get close. Braille display works more directly at the

character ...