In the Shounen verses Lum and her entire Race of the Oni are able to catch A Throat Infection that would change their Voices into what can only be described as A British Accent, and none of them even come close to realizing it's A British Accent as they have rarely been to earth before.

Of course, the Throat Infection could easily be cured by Honey and Tea but it would quickly Jump ship to Humans changing their voices slightly as well as if it was A different person Voicing them or Just A Different Accent.

Smith Fearing this would Jumo ship to Monster would quarantine Lum into A room until Suu serves her every need unable to catch any Virus or Infection, and of course, she is able to copy Y/n which makes Lum feel much better.

Of course, the only person to Catch it is Usagi who sounds like she was Voiced by A Different woman and She gets Quarantined as well.

A/n: Yes this is supposed to explain the Terrible BBC Dub of Urusei Yatsura and Those really old 90s Dubs like Sailor Moon, In case you're wondering.