Quote Originally Posted by Maat Mons View Post
Complete Arcane has rules for Mastering a Foreign Spellbook on page 140. It lets you "use the foreign spellbook as your own." Though low-level characters will need magical aid to consistently hit the DC.
It is a lot easier to make the "take 10" every day to decipher the spell to memorize for one day. You only need to master it if you don't want to have to roll. But yeah, eventually it is expected that the army will master it, getting a guidance+fox cunning or whatever to help the process along.