Yes there is, it is a rarely known thing
ok so I showed the M5 meet guys last year during the summer and they all went nuts as to how simple but great it was to shut that damn women up lol.
here is what you do,
when you are in your nav put the cursor meaning use the right button to move the cursor on to the instruction field which has a small speaker like icon on the side of it. If you press the right button down for about 3 seconds you will see that there will be a red bar that corsses over the speaker icon and then you will not have the gilr annoying nav commands. To set it back on just press the button once and voila.
I personally have never used the nav with the women talking I always just muted her.