8. A system comprising: a memory; and a processing device coupled to the memory, the processing device configured to: generate a set of vectors of parameters of a translation system that uses syntactic and semantic descriptions; translate, by the translation system using the vectors of parameters, a natural language text to produce a first plurality of translated texts; determine a first vector of translation quality ratings reflecting translation quality of the first plurality of translated texts; modify at least one parameter of each vector of parameters to produce a plurality of vectors of modified parameters; translate, by the translation system using the vectors of modified parameters, the natural language text to produce a second plurality of translated texts; determine a second vector of translation quality ratings reflecting translation quality of the second plurality of translated texts; and responsive to determining that an element of the second vector of translation quality ratings exceeds a corresponding element of the first vector of translation quality ratings, modify a vector of parameters based on a corresponding vector of modified parameters.
8. A system comprising: a memory; and a processing device coupled to the memory, the processing device configured to: generate a set of vectors of parameters of a translation system that uses syntactic and semantic descriptions; translate, by the translation system using the vectors of parameters, a natural language text to produce a first plurality of translated texts; determine a first vector of translation quality ratings reflecting translation quality of the first plurality of translated texts; modify at least one parameter of each vector of parameters to produce a plurality of vectors of modified parameters; translate, by the translation system using the vectors of modified parameters, the natural language text to produce a second plurality of translated texts; determine a second vector of translation quality ratings reflecting translation quality of the second plurality of translated texts; and responsive to determining that an element of the second vector of translation quality ratings exceeds a corresponding element of the first vector of translation quality ratings, modify a vector of parameters based on a corresponding vector of modified parameters. 10. The system of claim 8 , wherein determining a first vector of translation quality ratings comprises determining a plurality of Bilingual Evaluation Understudy (BLEU) scores reflecting translation quality of the first plurality of translated texts.