It depends on how you want this new dialogue to be connected to the dialogue that Muni has with the anonymous American. It is clear that the chief feature of the dialogue that Muni has with the American is that both are unable to understand each other and both know only a tiny amount of the other's language. They therefore engage in massive coversations about topics that the other has no idea about. The American therefore proposes buying the statue whereas Muni thinks he is offering to buy his goats. Even if they were able to communicate, the way in which the American talks about the statue and how it would look in his sitting room and how, for Muni, the statue represents a guardian who looks after him, it is suggested that they would not be able to understand each other anyway. They come from two completely different worlds.
A dialogue between Muni and his wife therefore might try and pick up on this theme and present the miscommunication that goes on from their two very different perspectives. You might like to think about how Muni's wife bears the main burden of providing for herself and Muni and how this might impact their communication. At the same time, Muni's role as a male without a specific job might be something that could enter the dialogue. The point would be to ensure that, as with the American, Muni and his wife are unable to communicate and come from two very different perspectives.