This link to the New England Journal of medicine shows oral droplets formed by talking. Watch the video.
https://www.nejm.org/doi/full/10.1056/NEJMc2007800
Here’s another link to an article discussing viral shedding and transmissibility.
https://www.nature.com/articles/s41591-020-0869-5
A lot of data and science speak but here is the short summary:
Timing of viral shedding & transmissibility: Reporting in Nature Medicine, researchers in China examined viral load data on some 90 COVID-19 patients, as well data on the timing of transmission among nearly 80 transmission pairs (that is, one person likely infected the other). Combining these data — and assuming an incubation period of 5.2 days — the researchers conclude that infectiousness began 2.3 days before symptom onset and peaked 0.7 days before symptoms began. They also estimate that presymptomatic transmission accounted for 44% of secondary cases among the transmission pairs.
The main take away is person A can infect a lot of other people before person A shows any symptoms.
Where a mask.