"I think my mum has the foulest mouth of anyone I've ever met"

In this quote, Kelly Osbourne is expressing her viewpoint about her mom's language. She believes that her mother has the worst or most offensive language out of all individuals she has come across. This could suggest that her mother utilizes a lot of blasphemy or repulsive language in her daily speech. It might likewise indicate that her mother tends to speak without filtering her words, which can be viewed as improper or offensive. Overall, this quote highlights the close relationship in between Kelly and her mother, as she feels comfortable enough to make such a declaration about her mom's language.