The Missionary Training Center (MTC), affiliated with the Church of Jesus Christ of Latter-day Saints, needs a reliable and cost effective way to measure the oral language proficiency of missionaries learning Spanish. The MTC needed to measure incoming missionaries' Spanish language proficiency for training and classroom assignment as well as to provide exit measures of institutional progress. Oral proficiency interviews and semi-direct assessments require highly trained raters, which is costly and time-consuming. The Elicited Imitation (EI) test is a computerized, automated test that measures oral language proficiency by having the participant hear and repeat utterances of varying syllable length in the target language. It is economical, simple to administer, and rate. This dissertation outlined the process of creating and scoring an EI test for the MTC. Item Response Theory (IRT) was used to analyze a large bank of EI items. The best performing 43 items comprise the final version MTC Spanish EI test. Questions about what linguistic features (syllable length, grammatical difficulty) contribute to item difficulty were addressed. Regression analysis showed that syllable length predicted item difficulty, whereas grammar difficulty did not.