Sketch-thinking in the design domain is a complex representational activity, emerging from the reflective conversation with the sketch. A recent line of research on computational support for sound design has been focusing on the exploitation of voice, and especially vocal imitations, as effective representation strategy for the early stage of the design process. A set of introductory exercises on vocal sketching, to probe the communication effectiveness of vocal imitations for design purposes, are presented and discussed, in the scope of the research-through-design workshop activities of the EU project SkAT-VG.