Custom Open Source Assistive Technology Software.

Home -> PowerTalk

PowerTalk is an example of Open Source Assistive Technology Software, or OATS. Find out more about OATS on the Fullmeasure.co.uk home page.


News Extra:You can now donate funds to our projects online.
Jambu will now use Linux Screen Reader as the platform.


PowerTalk 1.2.10
Automatic speech for PowerPoint presentations.

PowerTalk is a free program that automatically speaks any presentation or slide show running in Microsoft PowerPoint for Windows.

You just download and install PowerTalk and while you open and run the presentation as usual it speaks the text on your slides. The advantage over other generic 'Text To Speech' programs is that PowerTalk is able to speak text as it appears and can also speak hidden text attached to images.

Speech is provided by the standard synthesised computer voices that are provided with Windows.

PowerTalk was created 4 years ago in response to an open letter calling for help from a person with Asphasia. This appeared in Ability magazine, 'Campaigning for Accessible IT' published by John Lamb Media for the British Computer Society Disability Group in association with AbilityNet.

The OATSoft website is home to PowerTalk and many other Open Source Assistive Technology Software (OATS) projects.



  1. Aids you if you have difficulty speaking or you have an audience that contains people with sight problems (visual impairments, low vision or blind) or who have dyslexia;
  2. Helps you access presentations when there is no speaker and you are partially sighted;
  3. Creates engaging school activities such as reading stores created by students;
  4. Simple to use as you just select a presentation and it runs in PowerPoint as usual;
  5. Speaks the text on any presentation and uses standard Windows speech;
  6. Waits for text to appear and animation effects to play before speaking;
  7. Will speak hidden 'alternative text' for pictures, graphics shapes and text;
  8. Lets you add instant narration to presentations without the need to record speech;
  9. Is a useful tool for testing presentation accessibility when using a screen reader;
  10. Is mature with 1000s of downloads and several reviews from people who have found it useful;
  11. Free (gratis - as in 'free beer'). No purchase, registration or adverts, you just download and run it;
  12. Free (libre - as in 'free speech'). The Open Source License guarantees you the freedom to make copies and to alter its behaviour;
  13. Is listed on DMOZ and on Google web directories;
  14. Anyone can contribute to the project and developers will find it is a SourceForge project;
  15. Is a featured project in the OATSoft Open Source Assistive Technology Software project which brings the benefits of Open Source software to Assistive Technology users;


Downloads - Getting PowerTalk.

PowerTalk requires that you have PowerPoint 2000 (or later) and the Microsoft Speech API (SAPI) 5.1 (part of Windows XP). This is explained below.

Get PowerTalk Click on this icon to download the PowerTalk 1.2.10 [2.8MB] installation program. Once downloaded, Open/Run the installer and after the installation is complete you can open the demo presentation to test PowerTalk works correctly. You can install 2 additional free voices (Mike and Mary) with the SAPI Text To Speech (TTS) components [12MB]. The Using PowerTalk section below describes how to use PowerTalk on existing presentations.

Previous versions of all files can be found at the SourceForge PowerTalk Project Files Page.

Being an Open Source product, the source code [60KB] is freely available for those who wish to see or use it. Please see the license section below for terms.

Requirements, what you must have to run PowerTalk.

PowerTalk runs on Windows 98 (SE), Windows ME and Windows XP. It is expected to run on Windows NT 4.0 and Windows 2000. It is unlikely to run on Windows 95 or the initial release of Windows 98.

You must have PowerPoint 2000 or later installed. Unfortunately the PowerPoint viewers are not useable as they do not provide the basic functionality that PowerTalk requires.

The Microsoft Speech API 5.1 (MS SAPI 5.1) must be installed and if you have Windows XP you will already have it. For other versions of Windows you can download and install the SAPI Text To Speech (TTS) components [12MB]. This download can also be used with Windows XP and will then add 2 voices (Mike and Mary) to the single voice that is supplied with XP (Sam). To check if you have SAPI installed, look for a voice called 'Microsoft Sam' in Control Panel's Speech Settings (Start -> Control Panel -> Speech -> Text To Speech). Please note that the PowerTalk cannot use the earlier SAPI 4, although it is apparently possible to have both SAPI 4 & 5 installed on the same machine.

Basic sound capabilities are required. Most PCs with a sound card or 'on board' AC'97 sound will need only the addition of a simple powered speaker(s). Older PCs, or those that can only produce simple 'beeps' trough an internal speaker, may require additional sound hardware. You can test your PC's sound capabilities with the 'Preview Voice' facility in the Control Panel's Speech settings.


Using PowerTalk.

Opening Presentations.

There are a number of ways to get PowerTalk to narrate a PowerPoint Presentation (.ppt file) or Slide Show (.pps file):

Note: ppt and pps files are identical except for the ppt/pps part of the filename, the difference being what happens when they are opened. A .ppt file may be be saved in PowerPoint as a .pps file or else a .ppt file can be simply renamed as a .pps.

  1. Open a Slide Show. See below for details.
  2. Right click on a Presentation or Slide Show and select 'Narrate with PowerTalk'.
  3. Drag a Slide Show file onto a PowerPoint program shortcut.
  4. Browse to a Presentation or Slide Show using the dialog that appears when launching PowerTalk from the Start menu. The initial folder used may be specified using the shortcut 'Start in' property or adding the folder name as a parameter.
  5. Create a specific shortcut. Specify PowerTalk.exe as the target and the presentation file as a parameter(e.g. "C:\Program Files\PowerTalk\PowerTalk.exe" "MyShow.ppt").

By default PowerTalk will narrate Slide Shows when they are opened outside of PowerPoint (e.g. by double-clicking in Windows Explorer). Slide Show files may still be shown without narration by opening within PowerPoint or right-clicking on them and selecting 'show'. During installation there is an option to disable this feature and another option to enable it for Presentations. This behaviour may be changed at a later time by using the PowerTalk settings option in the startmenu (or as follows: open Windows Explorer (Windows key + E), select 'Tools' -> 'Folder Options' -> 'File Types', type 'PPS', select 'Advanced', select 'show' from the list (or 'open' for .ppt files) and then select 'Set Default').

Speech Order and Timing.

Text can be entered on a slide in either a single text box or split into multiple boxes and these are handled slighty differently.

The text in any single box is spoken continuously from top to bottom. Individual boxs are spoken in the order they are added to the slide. There appears to be no way to alter this and the way to force a different order is to create a new slide and copy the text boxes (hint click on the box border and copy).

Animated text is spoken in the order that the animations play, waiting for each to complete before speaking the next. However if a number of animations are used within a single text box, PowerTalk waits for the first animation only and then speaks all the remaining text. You may want to break the text into separate boxes and animate each.

Alternative text set for any object is processed in a similar way.

Speech Options.

The voice used and the speed of narration can be changed with the settings in the 'Speech Settings' section of Control Panel (on the 'Text To Speech' tab). There is a PowerTalk startmenu item that opens these settings.

Windows XP comes with as single voice 'Sam'. The 'SAPI TTS components' download available in the Downloads section will add 'Mike' and 'Mary'. A range of additional SAPI 5.1 voices are available and examples include AT&T Natural Voices, Nuance RealSpeak, Neospeech and IBM ViaVoice

The first time that PowerTalk is run you may notice a small delay as it analyses your PowerPoint and Speech API installations.


Support and getting help.

PowerTalk is very simple to install and run if your machine meets the requirements. If you are getting pop-up errors indicating problems with SAPI please ensure that you have SAPI 5.1 and not SAPI 5.0.

If you have problems or would like discuss PowerTalk you can email powertalk@fullmeasure.co.uk.


License, what you are allowed to do with PowerTalk.

This software is Open Source Software, that is, non-proprietary and is issued under the GPL license. You are free to copy or modify it as you like as long as you do not use it as part of any proprietary software. If you make any changes we would be very interested to know about them so that we can include them into the main release.


Change History.

Several improvements have been made since it's inital release and details can be found in the Project News. This information is also available as the XML/RSS feed RSS feed (See introducing XML/RSS Feeds).



The person for whom PowerTalk was created for submitted a review to Ability magazine. A subsequent article on PowerTalk and OATS also appeared.
There is a concise product summary available at the TechDis Accessibility Database.
Geetesh Bajaj has written a review and tutorial on his 'treasure trove' PowerPoint site 'Indezine'.


Contributing to the PowerTalk project.

As PowerTalk is OpenSource Software you are encouraged to contribute your ideas or to help develop it. If you find PowerTalk useful you might also like to donate funds towards developing it and other OATS projects. There are a few ideas for enhancements and bug fixes that you might like to work on. PowerTalk is a SourceForge project.


Creating Accessible presentations.

PowerTalk does a good job of making any presentation more accessible by automatically speaking the text. It can narrate animated text as it appears and will also speak PowerPoint's 'Web Alternative Text' intended for Web Browser use. Thus apart from being an accessibility tool in its right PowerTalk can be used to test how a presentation will sound with a other tools such as screen readers.

There are many techniques and tools for creating truly accessible presentations. A good place to start research is Glenna Shaw's excellent and thorough article The Incredible, Accessible Presentation.

Writing Text to Improve Synthetic Speech provides simple guidelines that can be applied when authoring text in order to maximize the quality of sythetic speech output.

Although the the speakers delivery is more important than the text on the slides there are general guides to writing clear English that will help make your message clear. MENCAP have a guide to Making your web site accessible for people with a learning disability that has much good advice on content creation. Writing Global English from Audience Dialog provides background and How to write Global English gives specific guidelines for writing to include people whose first language is not English. I think the principles should also apply when writing for those with learning difficulties and will help improve readability in general. Both dyslexic.com and Plain English Campaign have some great resources.

For some light relief you could read Edward Tufte's article on how PowerPoint corrupts. It is also available 'remixed' as a presentation. The opposite view is presented by 5 others.


Project Notes.

PowerTalk was originally conceived as a solution to a specific need and also to demonstarate the power of Open Source software for Assitive Technology solutions. Open Source offers many advantages to users and these may be especially important to users of Assistive Technology. Some of the advantages are; low cost, reliability, fast access to changes or fixes and availability. 'Open Source' is also called 'Free', FOSS and FLOSS software.

The code was donated to the Speechmakers project. Speechmakers aims to provide flexible and low-cost solutions to enable people to communicate more easily with others. It uses the latest technology and research to provide solutions to individual needs. The flexibility and power of modern Computers is harnessed by using high quality and innovative software created by a team of developers, students and volunteers. Software is released under an Open Source license, meaning that it is low cost and that changes can be made easily, for example if you would like new features or find bugs that need to be fixed.

PowerTalk will be a featured project in the OATS Open Source Assistive Technology Software project. OATS will make the great benefits of Open Source software readily available to Assistive Technology users.

PowerTalk clearly demonstrates how a small amount of custom scripting code can transform todays highly customisable applications to meet a user's specific requirements. I am keen to develop this idea into a service providing a repository of such programs and templates meeting specific needs. A key part could be an an active community of users providing requirments, ideas and discussion. If you are interested or have any ideas please contact me.

The Python program language was used to create PowerTalk. Python is a powerful, high-level, flexible and extensible language that is Open Source. It is a clean and easy to develop in and is fun! A large active community exists who have developed a massive range of high-quality library modules covering most conceivable programming tasks.



Ross Gravel for the original request and Ability Magazine for publishing it
Simon Judge for the Speechmakers Project, help, ideas, much support and bandwidth
Glenna Shaw for the 'get powertalk' graphic
Guido van Rossum and many, many others for Python
Mark Hammond for the Python Windows extensions and help with COM event problems
Gordon McMillan for the Python installer
Jordan Russell for the unrivalled Inno Setup
Bill Gates and Microsoft for Windows, PowerPoint and SAPI
Richard Stallman for the Free Software concept, GNU and all that has followed
DMOZ and Google for research tools
Jason Clifford for UKFSN for 'Free Software' friendly ISP and hosting services
Chilkat Software for 'ZIP 2 Secure EXE' used to create SAPI TTS installer
Bruce Ingraham & Emma Bradburn for the stylesheet used for this text
SourceForge for OpenSource project hosting services

SourceForge.net Logo Valid HTML 4.0! Valid CSS! Level Triple-A conformance icon, 
              W3C-WAI Web Content Accessibility Guidelines 1.0 Bobby WorldWide Approved AAA Bobby WorldWide Approved 508

Site Index | Related Pages | Powered by Wanabo