The study investigates the emission of particles during human speech and finds that the rate of particle emission is positively correlated with the loudness of vocalization, ranging from approximately 1 to 50 particles per second for low to high amplitudes, regardless of the language spoken. A small fraction of individuals, known as "speech superemitters," consistently release an order of magnitude more particles than their peers. The results suggest that unknown physiological factors vary significantly among individuals, affecting the probability of respiratory infectious disease transmission and explaining the existence of superspreaders who disproportionately contribute to outbreaks of airborne infectious diseases. The study also highlights the potential for speech to be a significant source of particle emission, which could increase the risk of transmission to nearby susceptible individuals.The study investigates the emission of particles during human speech and finds that the rate of particle emission is positively correlated with the loudness of vocalization, ranging from approximately 1 to 50 particles per second for low to high amplitudes, regardless of the language spoken. A small fraction of individuals, known as "speech superemitters," consistently release an order of magnitude more particles than their peers. The results suggest that unknown physiological factors vary significantly among individuals, affecting the probability of respiratory infectious disease transmission and explaining the existence of superspreaders who disproportionately contribute to outbreaks of airborne infectious diseases. The study also highlights the potential for speech to be a significant source of particle emission, which could increase the risk of transmission to nearby susceptible individuals.