Speaking Different Languages Impacts Size-Resolved Exhaled Breath Aerosol Particle Emission

Aerosol transmission plays an important role in airborne-spread diseases. The transmission variations across language-usage regions were observed during COVID-19, however the potential differences from languages on aerosol transmission are poorly understood. Here, fifty-one multilingual volunteers were recruited to speak same-semantic dialogues in three languages selected from eight different languages studied to investigate the emission characteristics of exhaled aerosol across languages. The findings revealed that the size of exhaled aerosol particles generated by speaking was predominantly concentrated below 1 μm. The emission loads of exhaled aerosols during speaking and the associated potential risk of aerosol transmission across languages showed notable discrepancies. Additionally, the individual physiological factors such as age, gender and body mass index (BMI) also jointly influenced the exhaled aerosols during speaking. The machine learning model of random forest regression further revealed that language differences had a considerably greater impact on size-resolved exhaled aerosol emission concentrations than gender, but not than BMI. Thus, different language usages can influence the emission concentrations of exhaled aerosol during speaking, thereby impacting the potential for aerosol transmission across languages. This linguistic-induced diversity of transmission potentials could have played a non-negligible role in the disparate global dissemination patterns observed in aerosol-transmitted pandemics including COVID-19.