After being told off by Lionel for being only coldly polite to their new American neighbours, Imogen tries to break the ice at dinner by using some American expressions she just picked up. Everyone else laughs their heads off, and tells her that the phrases she used are only said as a joke, or written in the comic newspapers and dime novels.
Lionel: Go on, Moggy. You're doing beautifully. Nothing like acquiring the native dialect to make a favorable impression in a new country. Oh, wherever did she learn 'catawampus'? I shall die of it.