The theory identifies the mental and cognitive processes involved in both oral and written translation: understanding the text, deverbalizing its language, re-expressing sense. For the purposes of translation, languages are a means of transmitting sense, they are not to be translated as such. Although translation involves the use of correspondences, translators generally set up equivalence between text segments. The synecdochic nature of both languages and texts, a phenomenon discussed in the book, explains why translation is possible across language differences.