When Archer learns that the disease is affecting one out of every three Valakians he says "so it's become a full blown epidemic", which is technically incorrect. An epidemic is when an outbreak of a disease rapidly spreads to a large percentage of the population, but it is limited to a local geographic area. When a disease spreads beyond that initial area and begins to affect multiple regions or continents it then becomes a pandemic. For example when COVID first broke out in the Wuhan province of China it was an epidemic at that point, but once it spread beyond that region and then to the rest of the world it then became a pandemic.
When discussing Phlox's marital situation at the Menk camp, Ensign Cutler mispronounces Denobulans as 'Denoblians.'