This work examines the acoustical aspects that emerge from the self-properties of the various geometrical shapes. For this purpose, 16 shapes (625 m2 each) were categorized and acoustically tested using principally ODEON ver. 4.2. The main objective is to establish a relationship between room shape/form and the intelligibility of speech expressed in five acoustic indicators. For this objective, new architectural indicators were developed and a complete set of adopted acoustic indicators were suggested to judge precisely the quality of speech in a room. The work was carried out in three phases. The first investigates Shape-Acoustics relationship (Chapter 2). The second investigates Volume-Acoustics relationship (Chapter 3) and the last investigates Form-Acoustics relationship (Chapter 4). While Chapter 1 is an introductory part that reviews the theoretical background of the work, Chapter 5 presents the conclusions and the main findings of the work. This is perhaps the first time to visualize rather than describe the type and distribution of the acoustical fields within a room. It should be especially useful for architects and researchers involved in the design of speech rooms.