Sharon,
Wow, I salute your efforts to be with your students one on one. Since your students do grasp conversational English take that knowledge to another level and teach them "Conversational Testing" Divide the testing process in to 3 parts Pretest, test and post- test. Give them a vocabulary for Pretesting. Instruct them on words that they need to understand when they will take a test and follow with vocabulary for true and false, multiple choice and call it "conversational testing" so they become familiar with the testing vocabulary. You can also use the Spanish version of directions followed by the English version. You have gone the extra mile by having your testes translated.
Arlene Muller