• BrowseAloud
  This package requires subscription by site publishers, but is a free download for end users. High quality synthetic speech can be streamed from a hosted service or the application is able to make use of local TTS built into Windows and OSX. Particularly usefully for ID users are features such as text being highlighted is it read aloud and the ability for the application to work either transparently or by following mouse focus in a more interactive fashion. License costs to Website publishers vary greatly, for non-profit organisations BrowseAloud is a reasonably cheap solution, but licensing costs for larger commercial sites are much greater and server-side solutions are likely to be more cost-effective.
• FireVox
  FireVox is a free extension to the Mozilla Firefox browser. It can be configured to work with a range of cost-free and commercial TTS systems. Although essentially targeting technically able VI users, it can be configured to work transparently or to require only minimal user interaction. FireVox is a very effective and constantly improving solution that works well on most websites, particularly for more able or semi-literate users.
• TextAloud
  TextAloud is an inexpensive third-party TTS helper application for Windows systems – and the biggest-selling application of its type. It provides a page reading toolbar for Internet Explorer and Firefox in addition to document and clipboard reading facilities. As with BrowseAloud, spoken page text is highlighted synchronously to provide essential contextual cues. Although it includes more complex functions, TextAloud can be configured to read webpage text automatically and the browser toolbars themselves are both simple and clear.
• VoiceOver
  VoiceOver is the built in spoken interface to Mac OSX targeting VI users. While it’s possible to use VoiceOver as page reading software, the verbosity of the application presents considerable barriers for ID users. Use of the OSX speech service discretely to read page text is a more manageable solution, though not one which enables interactive document reading.
• Windows Narrator
  Narrator is Windows’ built-in spoken interface and as with VoiceOver, significant verbosity provided in respect of its intended audience prevents its effective use as a discrete page-reading application by most users with ID.

text-to-speech application‘read aloud’ function

Server-side Text-to-Speech (TTS) Applications

• ReadSpeaker
  Example Site ::  www.cheshire.gov.uk
  ReadSpeaker has been deployed in the UK by several local government websites and provides high-quality streamed TTS and optional additional navigation and display controls intended to enhance usability. ReadSpeaker are also developing a simpler tool, WebReader, which is currently in Beta and targets smaller businesses and personal sites. A further application, SpeechMachine, provides an on-demand TTS service via a simple HTTP API. Most of the UK sites we tested which included ReadSpeaker worked only erratically, although it was unclear whether this related to the stability of the application itself or difficulties in respect of its implementation by site developers.
• VoiceForge
  VoiceForge, from the developers of the Cepstral speech engine, provides high-quality hosted TTS services via a SOAP API. An impressive range of voices and languages are available, though with charges made on a per-stream event basis this solution may work out expensive if a large volume of requests are expected.
• MediaSemantics, Character Server
  This technology powers many popular avatar based systems such as  SitePal. A hosted per-stream service is available, but running Character Server locally provides a comparatively cheap route to licensing the  Loquendo TTS system, probably the most impressive TTS application currently available and often prohibitively expensive to deploy. Character Server provides a range of sophisticated scripted and dynamic animation functions and includes support for an AIML based knowledgebase and autonomous agents. While primarily aimed at presentational content and elearning applications, it is easy to implement as an on-demand TTS system and provides a visual focus, including synchronous captions, which ID users may find more engaging than the ‘disembodied’ speech of many text-helper systems.
• IBM Easy Web Browsing
  Easy Web Browsing provides a number of accessibility and usability enhancements targeting novice and senior audiences with VI. In addition to page-reading and context-sensitive screen magnification, the application provides a number of controls to support navigation and display customisation. The application runs fullscreen by default providing a discrete console-like interface, rather than integrating into the browser or webpage as a toolbar. For end users the installation is cost-free and impressively painless although only supports Windows operating systems. License costs, which include developer support, are not inconsiderable and targeted publishers are probably larger corporate clients.