Round table

I play through GR. When I press the F5 key (refresh in the browser), some guy with a strange voice starts saying something. Does anyone know how to remove this?

Maybe it was your own voice? :) The F5 key is like the button on a radio: you press it and speak into the microphone, so that your teammates can hear you. In Ranger, other keys like F6, F7 are also used.
In the Gameranger settings:
Edit -> Options -> Voice
uncheck all the boxes in this section. This will simply disable voice playback.