Hi there!
I always use a nice utility called
SHOOT for have voice recognition with my games under XP and now I prepare a profile for SH5.
You can download SHOOT + required files
here
note: the more you "train" the "API 5.1-compatible speech recognition engine" the recognition will be better. Here I just train it once and all is going almost perfect!
I use SHOOT 1.6.4 under XP SP3

If that version didn“t load the profile for you try 1.6.3 instead... (thanks Thresher for the tip!)
My profile is compatible and intended to work with "
Stormy`s DBSM collection SH5" MOD
(You can use it without that MOD enabled but you will have to change many of the keys used by the profile. easy XML Editing...)
DOWNLOAD PROFILE
(is compatible with spanish keyboard but I think the only thing you will have to edit using english keyboards is the rudder settings. For that open the XML with notepad and search for the keys you want to change, even you can change the "phrase" you want to say for an specific option

)
So load Shoot , load the profile under shoot, load the game and for activate the speech recognition while playing press " * " in the numpad while you speak to the microphone....

(you can also configure that key at the profle)
you can print the command table for easy learning, just select FILE > EXPORT under shoot and you can have a .html with the table of voice commands...
hope you will enjoy this!