Thesis (M.S., Psychology) -- University of Idaho, 2016 | It is essential that unmanned aerial vehicle (UAV) operators in one location communicate clearly with UAV operators in other locations as well as Command, Control, Communication, Computer, and Intelligence/Information (C4I) forces. In 2008 the Air Force used a Modified Rhyme Test (MRT) to evaluate the Speech Intelligibility (SI) of a new voice communications system on the Global Hawk UAV. The raw data from these tests were analyzed for differences in SI between a full MRT of 50 words and subsets of progressively decreasing size, hereafter referred to as a reduced Modified Rhyme Test (rMRT), using five less words for each subset. If no differences in SI exist between the MRT and a subset of size n < 50, then it could be concluded that test time and resources could be saved by using an rMRT. The results of this study concluded that an rMRT of 30 words would be sufficient.