A computer system and method for natural language translation uses a translation process to translate a source natural language segment (e.g. English) of one or more source words/elements into a target natural language (e.g. German) segment of one or more target words/elements. An evaluation module determines a confidence measure of the natural language translation. Typically, the confidence measure indicates less confidence as the complexity of the translation increases. Various novel features for determining complexity and confidence measure at different steps in the translation are used. The translation process can be terminated if the confidence measure fails to meet a threshold criterion.