The videos above demonstrate the controller utility Glove Pie being used to play games with voice alone. Alex Kostov was behind the Track Mania Nations demo (giving thanks to InsaneLogic for help in creating the script). The FIFA demo is by Bill Donegan of SpecialEffect.
Glove Pie relies upon a scripting language, which is a very basic form of programming. It may well be worth persevering with as it is hugely versatile. You can connect many Wii compatible devices to your PC, Midi, microphones and more. This YouTube guide gives tips on how to use GlovePie with speech control.
For alternative speech access, see Say2Play or VAC (those links thanks to Mark Barlet and Steve Spohn of AbleGamers). All added to the Accessible Gaming Shop under Various and Software Utilities.