What is SALT?
Speech Application Language Tags (SALT) are a lightweight set of extensions to existing markup languages, in particular HTML and XHTML that enable multimodal and telephony access to information, applications and Web services from PCs, telephones, tablet PCs and wireless personal digital assistants (PDAs).
Comparing VoiceXML and SALT
VoiceXML and SALT are both markup languages. As one way of comparing the two, VoiceXML is a stand alone language while SALT is embedded into other web publishing languages, such as HTML or XHTML. For more on the differences between VoiceXML and SALT, check out the links to the left, or this article from Network World.
SALT is still a developing technology that is part of a broader effort focused on promoting “multi-modal” applications, or applications that users can interact with by means of keyboard, stylus, voice, etc. Multimodal applications are expected to be more broadly deployed as cell phones and hand-held computers merge into single devices that provide both local computation and connectivity to back-end servers. It is hoped that these applications will overcome the problems with the voice-only interfaces of phones and the GUI-only interfaces of hand-held computers.
In March 2002 the SALT Forum published a specification for speech tags called SALT (Speech Application Language Tags). In August 2002, The SALT Forum asked the W3C Multimodal Interaction Working Group and Voice Browser Working Group to review the SALT specification as part of their development of standards for promoting multimodal interaction and voice enabling the Web.
In early 2003, the SALT Forum overhauled its membership structure to allow for easier participation and collaboration by member entities. A number of featured products that incorporate the SALT specification have also been made available on the SALT Forum site, along with a number of other developer resources.