Destroyed text in sudo dialog
It's possible it could have messed up the Font cache.  Restart into Safe mode, (hold down shift after the boot chime) and release Shift when the grey screen and Apple logo appear.  When asked to log in, type in your password, then HOLD SHIFT and hit enter.  Reboot into OS X as normal and try again.

Hopefully it didn't delete a system font on accident.  Next, open Font Book, select all the fonts and choose Validate Fonts from the File menu.  Resolve any conflicts that it finds.  If you don't have a lot of non-standard fonts installed, you can choose Restore Standard Fonts from the File menu and reboot.  Hopefully it's something simple.