The aim of this doctoral research is to critically reflect upon and to make visible the manifold manifestations that are part of the field of improvisatory praxis in dance: techniques and technologies, in/outdoor laboratories, authorial research, somatic approaches, poetics of movement, scenic productions of artist collectives. Starting from the initial question: "Is improvisation (in contemporary dance) or does it operate as a language?", the general course of writing revisits the question of the principles/properties that prefigure a grammatical syntax of improvisation - a dynamic language that is always tied to its own praxis. In successive unfoldings, the multi-disciplinary relations with the other temporal arts (music and theatre), the domain of the ludic, the performative staging and the somotomotor-sensorial (aethic) readings linked to the role of the observer are revisited. The tone that guides the research is close to that of a literary essay, and was structured as a hypertext whose corpus is composed of three chapters and two audiovisual documentaries. Photographs and links from the computer network are added to the writing.