We ran Model 1 for three iterations, then the HMM model for three iterations, and finally Model 4 for two iterations, training each model until AER began to increase on our held-out cross validation data. "Inversion Transduction Grammar" (ITG) is the model of <cite>Wu (1997)</cite> , "Tree-to-String" is the model of Yamada and Knight (2001) , and "Tree-to-String, Clone" allows the node cloning operation described above.