You *should* take a look at pdftk. It is perfect for this and many other PDF related activities.
An action like this could be done for example with the following command:
Code:
pdftk yourbook.pdf cat 1-endodd output onelanguage.pdf
Of course this example will export the odd pages to a new pdf. For the even pages you need to replace odd by even of course. With this program you can also easily change sequence, rotate and my other things.