Shutter Speed Problem with Canon G11?

You have to hold down the exposure compensation button at the same time as turning the control dial.
The values appear on the control panel screen.

I found this on page 33 of the manual...
Set the mode dial to M and turn the control dial to set the value.
• To set the shutter speed: Turn the control dial.
To set the aperture value:Turn the control dial while holding down the
[+-](exposure compensation) button.

The exposure level indicator appears on the control panel screen, showing the difference (ranging from -3 EV to +3 EV) between the exposure value calculated by the currently selected aperture
and shutter speed compared to the exposure value considered optimum by the camera.

For direct control over the shutter speed, set your camera to the Tv (time value) mode. See the "Specific Shutter Speeds (Tv Mode)" section in the user guide (page 140 in my copy).

If you need the user guide, you may download a copy from here.

If your camera is a Rebel XS you should have a dial on the top right with a series of letters and icons. To set your camera so you manually control the shutter speed turn this dial too "TV" (Time Value). This setting will allow you to select the shutter speed and the aperture will open or close to achieve the correct exposure. The "M" is (Manual) where you would select both the shutter speed and aperture "AV" is (Aperture Value) where the user selects the aperture they want and the shutter speed increases or decreases to obtain a proper exposure. The "P" (Program) mode allows the camera to automatically select the shutter speed and aperture

Hello,
You may change your shutter speed in Manual mode only. So you should turn your mode dial button to M position. Then you may control both shutter speed and aparture value.

Hello,

Set the mode dial on the top of the camera to Tv.
Use the control dial on the back to change the shutter speed.
The aperture value is shown on the screen at the bottom.
If it is shown in red the picture will not expose correctly.
Adjust the dial until the value is white.

I hope this helps.