Hello Quentin,
You may want to see if any of the following may help with the Speech initialization failed message. Thanks.
Solution #1 - Delete L&H RealSpeak:
1. Click the Start button.
2. Choose Run.
3. Into the Open box, type
regedit
4. Click the OK button.
5. Double click HKEY_LOCAL_MACHINE.
6. Double click Software.
7. Double click Voice.
8. Double click TextToSpeech.
9. Click Engine.
10. With the word Engine highlighted, look at the right-hand section of the Window.
11. There are two columns of information. The left-hand column is titled Name.
12. Right click on L&H Realspeak, or ScanSoft.
13. Left click on Delete, close and reboot computer.
http://www.aisquared.com/forums/viewtopic.php?t=1055
Take care,
James