Co-speech gesture in monolinguals has been linked to several cognitive processes: prompting memory stores, conveying spatial concepts, searching for lexical equivalents, and supporting rhythm and cohesion. The production of co-speech gesture also occurs in spoken language bilinguals. Studies have demonstrated that bilinguals fluent in American Sign Language (ASL) and English (bimodal bilinguals) produce gestures at similar rates during conversation as do spoken English monolinguals, but that bimodal bilinguals use different gesture types. No previous study had looked at bimodal bilinguals engaged in the act of interpreting. This study examined the co-speech gesture of ASL-English interpreters as they interpreted from an ASL source into spoken English. The aim was to determine whether bimodal bilinguals in this condition gesture similarly to bimodal bilinguals in conversation. I used data collection and analyses methods employed by previous studies that examined co-speech gesture in bimodal bilinguals through the retelling of a cartoon. (Casey & Emmorey, 2009; Faust, 2012; Weisberg et al, 2021). However, unlike the previous studies, I also studied the rates and types of gestures that emerge during ASL-to-English interpretation. I then analyzed instances of co-speech gesture using the r studio statistical package. I found that the frequency and type of gestures produced by ASL-English interpreters during the act of interpreting pattern differently than those found in studies of both English monolinguals and English-ASL bimodal bilinguals in conversation. Specifically, interpreters gesture significantly less while interpreting than they do in conversation. These same bimodal bilinguals also gesture more than monolingual English speakers while in conversation. This result counters early findings that showed no difference between monolinguals and bimodal bilinguals in terms of gesture rate, but supports later studies that found bimodal bilinguals gesture at higher rates. My initial hypothesis was that lack of gesture while interpreting would impair the cognitive processes listed above and result in more disfluent speech. Instead, it appears that lack of gesture negatively impacted vocal tone. The results could be used in interpreter training to elicit more natural-sounding interpretations by encouraging interpreters to employ natural co-speech gesture while interpreting into their spoken language. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]