The investigator attempted to study the variance in production of the diphthongs 10T-1 and /du/ in three dialect regions of Indiana. The following factors were studied: 1) sex differences in pronunciation, 2) nationality differences in pronunciation and 3) the effect of population on production.The motivation for this research evolved from an interest in categorizing regional speech according to production. It appeared to the investigator that native Hoosiers might pronounce a given word in several different ways. For example, the observed pronunciation of the word "tire" was /tair/, /tar/, or /tar/: and the observed pronunciation of the word "tower" was /taur/, /tar/, /tar/, or /taer/. It was apparent that the pronunciation of the words "tired" and "tower,, differed in all productions. The pronunciation differences were apparently a product of various geographical locations of people. This factor prompted the investigator to study regional differences in the production of diphthongs in Indiana speech.The study will be valuable as a part of the entire study of speech characteristics of Indiana residents. It will contribute to a greater understanding and appreciation of geographical locations as a contributing factor to pronunciation.Using the hypothesis that there are three distinct dialect regions in the state of Indiana, it was the purpose of this study to determine whether trained judges could easily identify each region. The study will furnish evidence for or against the assumption that pronunciation does vary significantly in the state of Indiana.