Upon installing acroread to see if the text in a PDF I'd just created was selectable, I fired it up with the PDF in question. Is there a font ebuild that should've been pulled in that wasn't? A screen capture will be attached shortly. Reproducible: Always
Created attachment 114450 [details] acroread snapshot
Probably depends on your LINGUAS (which you haven't posted).
wow, your screenshot looks so much like windows.
Post emerge --info, please, then re-open. My guess is you've chosen a language that you don't have the fonts for. You could try removing ~/.adobe (rm -rf ~/.adobe), check LC_* and LANG are sane then re-launch acroread.