She is such a chatty Cathy, she never stops talking.
Она такая болтливая Кэти, она никогда не перестает говорить.
Definitions
A 'chatty Cathy' refers to a person, typically a woman or girl, who is excessively talkative or gossipy. The term originates from a popular talking doll named Cathy, which was known for its ability to speak various phrases.
