To prepare for the national norming of El Circo (the Spanish-language equivalent of the Circus Assessment Battery) three research questions were posed. First, will the presentation of test instructions in both English and Spanish significantly increase achievement? Second, what level of language competency is necessary for valid use of the various tests on nonlanguage skills in the El Circo battery? Third, how can this competency be assessed? Three El Circo tests, representing low, intermediate, and high requirements for understanding test instructions and responding appropriately were given to 154 Spanish speaking or Spanish surnamed preschoolers. Results indicated both languages should not be used for test instructions because there was no significant difference in achievement between groups assigned to this treatment and groups receiving instruction in the dominant language alone. The influence of language competency increased with the quantity of verbal instructions for the test. Prescreening to identify children with insufficient Spanish to benefit from El Circo was recommended. The Bilingual Syntax Measure and the El Circo Language Check were validated in this study for prescreening. Although parent and teacher assessments were also considered, neither added much to the accuracy of the screening. (CP)