The aim of this work is to present a brief analysis of the complex language that differentiates a patent from any other technical document. As far as Italian and Spanish patents are concerned, in fact, it is possible to identify a set of lexical, syntactical and textual characteristics that are the result of a well-balanced combination between technical and legal language in order to guarantee a consistent style to this unique genre. The second part of this work offers some general norms required to provide a literal translation of a patent before introducing some practical examples of translation from Spanish into Italian with a particular interest on the environment related lexicon present in a patent against marine plastic pollution.