Option 1:
That's strange. I'm unsure exactly what needs to be installed but check Xcode's preferences and see under the Downloads
tab you have the following:
I'm guessing whatever you need is in either the documentation or components.
Option 2:
Ensure you are using the latest Xcode (that is Xcode 5.1.1)
It could be you are using a BETA version of Xcode 5 which may not have came with all languages
Option 3:
If you installed simulator 7.1 before 7.0, you might need to install 7.0 still, as suggested by this: