SSML, a markup language to give control over how text is read aloud,
is nominally supported in several browsers. Unfortunately, like many
cutting-edge web technologies, it isn't evenly implemented. With no
TCK
against which to verify compatibility, developers are on their own to
try technologies and work around incompatibilities. In the case of
SSML, support seems very spotty, and the failure mode is severe
— the markup is read aloud, destroying the experience.
Tested Browsers
Firefox and Chrome were tested. SSML was provided to the Web Speech
APIs to be read aloud. Neither handled SSML in any of the following
forms:
<speak> tag only
speak tag with version attribute
speak tag with version attribute and XML doctype
As of this writing (June 2020), it does not seem feasible to use SSML
in production via the Web Speech APIs.