You are attempting to perform a Lite Touch installation of Windows 8.1 using MDT 2013 and you are halted on the Locale and Time page as the Language to install: field is blank with no drop down options, this stops you from continuing with the deployment.
As a work around to this issue I edited the CustomSettings.ini file to include statements to automate this part of the deployment wizard. I added the following statements into the CustomSettings.ini file;
TimeZoneName=GMT Standard Time
Although there may be reasons you do not want to automate this step, this worked around the problem for me and allowed me to continue with the OS deployment.