appears to work with pypy2_0 (including tests) seems also supported upstream https://github.com/Diaoul/babelfish/blob/master/.travis.yml#L8
I do not have pypy installed, but if upstream declares pypy as supported and tests work fine for you - commit :)
+ 07 Apr 2014; Julian Ospald <hasufell@gentoo.org> babelfish-0.5.1.ebuild, + babelfish-9999.ebuild: + add pypy2_0 support wrt #507072