Dont. Use. MonoLingual.
Believe me, you don’t want to. At least, head the warnings about not removing the different architectures (specially if you are on an intel Mac). I just spent the best part of the night, reinstalling Mac OS X and piecing my setup together from various backups.
How I found out? Ecto, a PowerPC program, crashed when I tried to post the last post. Monolingual had removed all traces of PowerPC executables and libraries from my system - including Rosetta…