question:  What are two examples of Groacian communication mechanisms?
context: You don't have to be crazy to be an earth diplomat—but on Groac it sure helps! I "The Consul for the Terrestrial States," Retief said, "presents his compliments, et cetera, to the Ministry of Culture of the Groacian Autonomy, and with reference to the Ministry's invitation to attend a recital of interpretive grimacing, has the honor to express regret that he will be unable—" "You can't turn this invitation down," Administrative Assistant Meuhl said flatly. I've been tied up every off-duty hour since I got here—" "You can't offend the Groaci," Miss Meuhl said sharply. "You've been here on Groac for four years, Miss Meuhl. "Mr. Retief, those are just the sort of questions we avoid with the Groaci. "The Groaci are a very sensitive race. The pale-featured Groacian vibrated his throat-bladder in a distressed bleat. "The impossibility of access to outworlders. The few Groacians on the street eyed him furtively, veered to avoid him as he passed. An elaborate one picked out in pinkish paint seemed to indicate the Groacian equivalent of a bar. A Groacian bartender was dispensing clay pots of alcoholic drink from the bar-pit at the center of the room. A tall Groacian vibrated his mandibles in a gesture of contempt. Retief backed into the opening to a narrow crossway and offered further verbal familiarities to the drunken local, who followed, furious. Retief backed, rounded a corner into a narrow alley-like passage, deserted, silent ... except for the following Groacian. Groacian gentlemen." Two Groaci wearing heavy eye-shields and elaborate crest ornaments indicative of rank rose as Retief entered the room. "One hour ago," The Groacian said, "a Groacian national was brought to hospital suffering from serious contusions. "You reopen an old wound, Mr. Consul. I understand that a Terrestrial task force stood off Groac and sent a delegation down to ask questions.
output:  Mandible snaps and throat-bladder bleats
options:  Mandible snaps and throat-bladder bleats  Mandible wiggles and eye clogs  Jaw snaps and jugular cracks  Jowl clacks and eye beats