This work tries to explore the mental processes of simultaneous spoken-sign language interpreters and the speech errors that occur when working from a sign language (ASL) into a spoken language (English). A short study was conducted with two native bilingual bimodal sign language interpreters to show that we have limited processing capacity when interpreting, and that there seems to be a trade off between our natural ability to automatically produce grammatically correct utterances in our native language and the mechanisms necessary to interpret simultaneously.