Have you installed elementary-tweaks per chance? (I see
Tweaks.vala in your terminal output) Unfortunately while a great application, it is reported to cause issues and is not recommend. This might be one of those issues? Try uninstalling it and see if the problem persists. If that fixes it I'd suggest posting a bug to the elementary-tweaks bug tracker.
Just for clarification,
gnome-control-center is a bash script that redirects to
switchboard, which is the actual name of the System Settings app in elementary OS.
Upon further inspection of your terminal output, it shows a segfault on line 20, which is where the redirection takes place. The actual command to open the keyboard settings dialog is
switchboard keyboard. Run that command directly and see if it gives any additional clues. If there is nothing obvious there, run it with the -d flag to show additional debug information.
switchboard -d keyboard.
You could try to reinstall switchboard and the keyboard plugin with-
sudo apt-get update
sudo apt-get install --reinstall switchboard switchboard-plug-keyboard
If a reinstall doesn't help, it is time to hit the switchboard-plug-keyboard bug tracker. See this answer for best practices in lodging bug reports. I notice there are several existing bugs related to crashing on there already that may be possible duplicates of yours.
Please update your question with the
-d output and a link to the bug report. Also consider including a link to this question in your bug report in case someone else comes along and solves your problem here.