Abstract: Methods, systems, and apparatus, including computer program products, for language translation are disclosed. In one implementation, a method is provided. The method includes determining, for a plurality of feature functions in a translation lattice, a corresponding plurality of error surfaces for each of one or more candidate translations represented in the translation lattice; adjusting weights for the feature functions by traversing a combination of the plurality of error surfaces for phrases in a training set; selecting weighting values that minimize error counts for the traversed combination; and applying the selected weighting values to convert a sample of text from a first language to a second language.