This text is a complement to the musical composition The Spell of Speech, a piece for actress, electro-acoustic sounds and live-electronics composed in 2004 as part of the requirements to conclude the Master’s degree in Electro-Acoustic Music at Dartmouth College. The core of this research is the relationship between speech and music composition. The first chapter presents a theoretical framework comprising evolutionary musicology and music cognition. The second chapter contains a historical survey of electro-acoustic music in which human voice plays a fundamental role. Finally, the third chapter analyzes the composition The Spell of Speech, presenting the main techniques used and the musical ideas involved.