I have installed a new 32 bits Scansoft voice (Jennifer) in my Windows 7 64 bits OS in order to be able to use from in one .NET application i'm developing.
The problem is that I when I call the method :
List<string> allInstalledVoices = new SpeechSynthesizer().GetInstalledVoices();
I only get one voice returned, the default Microsoft Anna Voice. but I can see all the installed voices in other text to speech application.
I found what the problem was. It turns out that when compiling the project to "Any CPU" (using Visual Studio 2008), the problem occurs. but when changed to x86, the problem doesn't appear anymore.