Who Speaks is an innovative application which allows users to analyze voice frequencies and recognize the number of speakers/voices in a room – we entered a new research projects related to the voice recognition and voice processing. The requirements were to have a possibility to register as many voice frequencies in one place as possible and to collect data about these voices/frequencies all in one application. Zesium created an innovative algorithm able to recognize voices at one place and make the communication between Android UI and backend side (RESTful services) possible. Application is able to recognize how many people are there in the room, based on their voice frequencies, and subsequently recognize and mark each speaker at the place. The created User Interface is able to name different speakers in the room, distinguish them and mark their voice each time they speak. The Who Speaks application is able to analyze and segment specific sequences directly from the raw data based on certain parameters from the algorithm. The challenge of the app development was to show graphical redistribution of specific speakers who participated in the conversation and to recognize their involvement and voices in real time. Technologies used in the development process of the application are: C++ and Android Studio.