One can test the concept as a conference call between cell phones (or use the audio-only versions of Skype, Zoom, Team, etc.); it is best using ear buds, with a microphone dangling on the wire, as an ear bud can block room noise.
But the goal is a low-tech setup for an entire dining room, always on and ready for dozens of quiet tabletop conversations without any plugging in or fiddling. Tall round tables could become quiet conversational hubs at cocktail parties. Think in terms of designing table decorations that contain directional microphones pointing horizontally and a speaker pointing up toward the ceiling. While some sound will be reflected back down, the path length between tables will be much longer, contributing less to room noise.
For the temporary stand-up party tables, battery power will be needed; for more permanently located tables, an overhead light might allow a thin 5V DC cable to be dropped.
Note that the device's loudness can be simply adjusted by leaning in toward the center of the table. That works when speaking as well. "Lean in!" substitutes for "Speak up!"
 The asymptomatic period, when an infected person is spreading the virus but not yet sick, is often as long as a week or more. And “Typhoid Mary” sickened over fifty people without getting sick herself. She denied everything and refused to take precautions even after physicians made it clear to her that she was killing people by spreading Salmonella typhi. Thus we speak of the “Typhoid Mary” Governors.