You can't change the layout in UO coz it's currently hard-coded (have asked for this a couple of times in the past).
For now, to work around it, you can modify your Windows settings. Control Panel->Regional Languages->Advanced. Change the key combo to toggle your keyboard layout or just disable the combo altogether if you don't need it. You can click on the language bar to change it instead.
Alternatively, if you don't need the extra language, just remove it.