Mr. Smith: "An Englishman's home is truly his castle." Mrs. Smith: "I don't know enough Spanish to make myself understood." (498-499)
The play ends with a long chain of non-sequiturs. Basically, the characters spout a lot of stuff that doesn't seem to be connected in anyway. In some ways, they barely seem to be communicating at all. This lack of communication could be seen as an indication that they are all quite isolated.