Systems and methods for multi-engine machine translations are disclosed. Exemplary methods and systems involve normalizing and/or tokenizing a source string using user-specific translation data. The user-specific translation data may include glossary data, translation memory data, and rule data for use in customizing translations and sequestering sensitive data during the translation process. The disclosed methods and systems also involve using one or more machine translation engines to obtain a translation of the normalized and/or tokenized source string.