This thesis presents a comprehensive view of the recently-established sphere of activity known as "extended vocal techniques", the now broadly disseminated phrase describing the vocal avant-garde. Emanating from a group of singer-researchers active from 1972 at the Centre for Music Experiment, University of California at San Diego, the term itself refers to those newly-invented or borrowed vocal sounds which are not identifiable as Western Art Music Phonation.
Because the term is negatively defined, it applies to a wide variety of sounds including precedents for which it is somewhat anachronistic yet appropriate. Chapter 1 describes earlier usages and the advent of singer-involvement in vocal experimentation. An interest in collecting and codifying vocal sounds led to the definition of the term "extended vocal techniques" and to the production of the EVTE Lexicon which is described in Chapter 2 along with two later catalogues of sounds. Practical aspects of sound production are clarified and the three lexicons contrasted with respect to organization and intent.
Chapter 3 introduces the question of usage, and describes the various applications of extended vocal techniques to performer-oriented improvisation and composition with the incumbent emotional, psychological and spiritual associations. Because of the emphasis on pre-logical response, this represents an oral orientation in contrast with the compositional application of extended vocal techniques in written form. Chapter 4 discusses various works including examples of repertoire generated directly from two of the lexicons described in Chapter 2. Observations are made regarding the artistic and aesthetic value of applied extended vocal techniques, based on the idea that certain applications are allied with the concept of vocal vanguardism and with individual avant-garde movements, whereas others relate to more universal principles of artistic expression.