F1 2015 Voice Commands on PC

[wikke1984]

hellow racers ,
can somebody help me out how to use vioce commands on my pc...

i never tested it out.
if i push on a button on my wheel the vioce commands come out but how can i select them ?
normally i just race with my speakers and no headset but ...

do i need to plug in my headset for controlling the vioce commands ?
or do i need a other program for letting it work.
hope people can help me a little bit.
big thx
wim