Gesture restriction decreases the quality in simultaneousinterpreting

Abstract Gestures integrate with speech and support planning and delivery. This study examined whether restricting gesture degrades simultaneous interpreting quality. Eight L1-Spanish interpreters rendered two matched English speeches (EN→ES) in a within-subjects design: gestural (as usual) and non-gestural (hands holding a table-mounted bar). Outputs were rated on accuracy, terminology, cohesion and prosody; pauses and self-repairs indexed fluency. Inter-rater reliability for total scores was acceptable (Spearman ρ = .614, p < .01). Quality declined without gesture: total weighted score 8.2 vs. 7.0, t test p = .0003. All criteria fell (accuracy p = .0001; prosody p = .0012; cohesion p = .0072; terminology p = .0185). Fluency worsened, with more pauses/self-repairs (21.3 vs. 27.6 per speech), t(7) = 3.58, p = .009. No participant improved on any criterion. Findings indicate that preventing gesture removes a resource that supports management of parallel demands on comprehension, memory, and production in a complex language task.