Languages for Specific Purposes and, even more so, medical texts, are typically characterized by the presence of a determined set of linguistic features. These are not only terminological, but also morphosyntactic traits (e.g. passivization and anonymization, nominalization, as well as information condensation), which differ from those of general language for their higher frequency. However, while highlighting the specialized nature of a text, they may impact negatively on its understandability, since they make it harder for readers to process information. The present paper aims at analyzing one of these morphosyntactic features, i.e. passive diathesis and related structures, in layperson summaries of clinical trials, a still widely unexplored text genre which is addressed to non-experts in the medical field and should therefore be comprehensibility-enhanced. In order to examine this phenomenon, a quantitative analysis will be carried out on a corpus of texts through two tools, Analyze My Writing and Ratte (whose results will also be manually checked), to calculate the frequency of passive sentences both in layperson summaries, in the English source text and in its German translation, and in their corresponding English texts for medical experts. The purpose is to ascertain whether the level of passive forms actually decreases in the comprehensibility-enhanced versions and in the translated texts, and to which extent. Furthermore, a second part of analysis will be conducted to examine also structures which are not considered by the software (e.g. passive forms with the auxiliary GET in English, Zustandspassiv as well as alternative constructions like the so-called lassen-middles or modal infinitives in German) and allow further reflections on the topic (such as passive functions, agents, and translation).
