I have not tried SH3Speech but I have solved a similar problem of how to make speech recognition work with Il-2: 1946 when running a Finnish version of 64-bit Windows 7 Home Edition.
I managed to change my Windows 7 into an English version with this program:
http://www.froggie.sk/
After changing Windows into an English speaking version, all speech recognition programs started working again, like they did before, when I ran XP.
Another solution would be to upgrade your Windows 7 into Professional version. I understand that the Pro version lets you change your system language at will.