W3C home > Mailing lists > Public > www-style@w3.org > December 2014

Re: [css-speech][css-content][mediaqueries] Making Generated Content Accessible

From: Daniel Weck <daniel.weck@gmail.com>
Date: Wed, 3 Dec 2014 13:50:08 +0000
Message-ID: <CA+FkZ9Gt8gr4=58KeWcwkvGWoLxzepDkD-m6Kv8gLmCXJKWpoA@mail.gmail.com>
To: James Craig <jcraig@apple.com>
Cc: Florian Rivoal <florian@rivoal.net>, fantasai <fantasai.lists@inkedblade.net>, Alan Stearns <stearns@adobe.com>, www-style list <www-style@w3.org>, "Tab Atkins Jr." <jackalmage@gmail.com>, fantasai <fantasai@inkedblade.net>
On Wed, Dec 3, 2014 at 3:43 AM, James Craig <jcraig@apple.com> wrote:
>
>> This raises 2 (related) questions. Is the introduction of this media feature sufficient to deprecate the “speech" media type into never matching? If not, can and should the same privacy model be applied to it?
>
> My understanding is that the speech media type is *only* useful for linearized audio-only media not intended for the screen, since it is mutually exclusive with the screen media type. Most assistive technologies operate on some concept of a "screen" (including screen readers for the blind) so the speech media type should never apply to screen readers or ScreenMagnifier+Speech utilities, but its possible there is some use case. For example, if you were to turn an EPUB into a generated TTS audiobook, the speech media type could apply. I don't know if any implementations support that, but you'd probably want to check with someone from DAISY before making it a No-Op.


Hello,

Yes, from a content design perspective, the 'speech' Media Type can be
used to define a "complete aural alternative to a visual presentation"
(full quote below), and as per the specification: such representation
would be mutually exclusive to other media types, when "rendered"
within a *given* canvas. The same applies to 'braille' (for example),
although the "tactile" Media Group also includes the 'embossed' Media
Type (conversely, 'speech' stands on its own).

I am not sure about the current state of screen-reader support for the
CSS Speech properties (formerly "Aural" stylesheets), let alone for
the selective application of properties defined within the scope of
the 'speech' media type. My assumption is that there are very few
implementations, most are partial, and based on the old "Aural"
specification.

"
The CSS Speech properties provide the ability to control speech pitch
and rate, sound levels, TTS voices, etc. These stylesheet properties
can be used together with visual properties (mixed media), or as a
complete aural alternative to a visual presentation.
"
http://www.w3.org/TR/css3-speech/#intro

The use of the 'speech' Media Type is merely a recommendation in the
context of EPUB3. The CSS Speech properties can be applied in the
default stylesheet of an EPUB XHTML5 document, irrespective of the
'speech' Media Type. I am not aware of any supporting e-reader
implementation (more often than not, the screen-reader would take care
of picking-up the CSS Speech properties anyway, but occasionally an
e-reader could also be "self-voicing", interfacing directly with a TTS
API, to programmatically pass the CSS parameters to the synthetic
speech engine).

More information about the historical shift from "aural" to "speech":

http://www.w3.org/TR/css3-speech/#background

Regards, Daniel
Received on Wednesday, 3 December 2014 13:50:34 UTC

This archive was generated by hypermail 2.4.0 : Friday, 25 March 2022 10:08:49 UTC