In this paper, we defend the idea that research on Gesture with Speech can provide ways of studying speakers’ conceptualization of grammatical notions as they are speaking. Expressing an idea involves a dynamic interplay between our construal, shaped by the sensori-motoric and interactive experiences linked to that idea, the plurisemiotic means at our disposal for expressing it, and the linguistic category available for its expression in our language. By analyzing the expression of aspect in Speech with Gesture (GeSp) in semi-guided oral interactions, we would like to make a new contribution to the field of aspect by exploring how speakers’ construal of aspectual differences grammaticalized in their language, may be enacted and visible in gesture. More specifically we want to see the degree to which event structure differences expressed in different grammatical aspects (perfective and imperfective) correlate with kinesiological features of the gestures. To this end, we will focus on the speed and flow of the movements as well as on the segments involved (fingers, hand, forearm, arm, shoulder). A kinesiological approach to gestures enables us to analyze the movements of human bodies according to a biomechanical point of view that includes physiological features. This study is the first contribution focused on the links between speech and gesture in French in the domain of grammatical aspect. Grammatical aspect was defined by Comrie (1976) [1989] as involving the internal unfurling of the process, «[...] tense is a deictic category, i.e. locates situations in time, usually with reference to the present moment [...]. Aspect is not concerned with relating time of the situation to any other time-point, but rather with the internal temporal constituency of the one situation; one could state the difference as one between situation-internal time (aspect) and situation-external time (tense) » (Comrie, 1976 [1989]: 5). Can kinesic features express and make those semantic differences tangible? When a speaker produces a gesture with specific physiological properties, for example a certain speed, is there an underlying source that motivates that speed? Could a speaker’s construal of the event, seen in her choice of grammatical aspect, lead to her performing a gesture with specific properties? This study is an attempt to tackle these questions and present new methods to analyze gestures.