Nishimura T., Miyachi S., Kaneko A., and Kinoshita Y. published their study in the US international journal Science.
Using imaging techniques with 43 species of nonhuman primates, they were successful in showing their voice box morphology and the uniqueness in humans. They demonstrated the vibratory properties and acoustic effects in nonhuman monkeys using experimental techniques, showing that the simplification of the voice box anatomy led to the evolution for complicated speech, linguistic communication in the human lineage.