I think it would ease things a lot, if language selection would always be done in text mode (similar to rescue mode or asktmethod). Graphical language selection is only used for graphical CD installs and so makes testing hard.
This isn't going to be changed -- text mode is significantly worse for making this selection as you can't get the native language displayed. You can boot with 'linux nopass' to get the graphical language selection on all install types.