Abby: Child's baby talk grates on woman's nerves

A woman who has been dating her boyfriend, Brad, for nine months is struggling with his daughter's behavior. Both partners have children, with Brad's daughter being slightly older than the woman's 7-year-old son. The woman reports that the young girl's persistent use of baby talk has become unbearable and is grating on her nerves. She has sought advice from Dear Abby to manage her frustration while maintaining her relationship with her partner.