The Baobab Larynx-7 was a model of reed whistle that allowed a being to communicate with droids in droidspeak. It emulated whistles, chirps, and buzzes which the droid could understand, assuming it did not already understand the language of said user.
The Larynx-7 was a popular model, however could easily be misused in the wrong hands. Once upon a transgalactic starliner, some Howler Tree children got hold of a Larynx-7 and commanded the entire droid service crew to engage in a cabinwide food fight. This forced the pilot to terminate the flight in the Gulf of Tatooine so as to clean the cockpit window. Thus the instrument was only to be used by adults.