I know I'm late to the party, but I'd like to provide a more complete answer and elaborate on my solution.
I run my uiautomation from shell scripts, here's my solution..
(You'll have to remove spaces etc)
settingsapp.sh
#!/bin/bash
sleep 5s
instruments -v -w MY_SIMULATOR_DEVICE_ID -t
/Applications/Xcode.app/Contents/Applications/Instruments.app/Contents/
PlugIns/AutomationInstrument.xrplugin/Contents/Resources/
Automation.tracetemplate /Applications/Xcode.app/Contents/Developer/
Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/
Applications/Preferences.app -e UIASCRIPT
/Users/ path to my js file/settingapp.js
settingapp.js
var target = UIATarget.localTarget();
target.delay(1.0);
target.frontMostApp().mainWindow().tableViews()[0].cells()
["General"].tap();
target.delay(1.0);
target.frontMostApp().mainWindow().tableViews()[0].cells()
["Language & Region"].tap();
target.delay(1.0);
target.frontMostApp().mainWindow().tableViews()[0].cells()
["Region"].tap();
target.delay(1.0);
target.frontMostApp().mainWindow().tableViews()[0].cells()
["United Kingdom"].tap();
target.delay(1.0);
So you could have several shell scripts, firstly one to set the language, then another to do screen shots, then run another switch to another language etc..
:)