I installed the latest beta and found a setting in the Admin Configuration-panel where I could change the default language. I chose Norwegian here (although I perfectly know Magento hasnt been translated into Norwegian yet), but then everything like uhm.. crashed.. (see screenshot).
I think you should modify the code so that it always falls back to English if a language you have chosen doesn exist, or isnt fully translated (or not even display other languages than those who are installed).
PS: This wasnt actually an “Installer-problem”, although I wasnt sure where to address it. Its both a Bug-report and a warning for you all not to change the default langauge in Magento
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