If you are in a car with a profane drunkard, you do not copy his actions, or, if obliged to address him, adopt his style of language.
The glaring defect in the manners and voice of the American girl is that she is "loud." German Gretchen or Irish Bridget is more likely to speak softly in public than her rich young mistress.

It is often a shock to the observer when sweet sixteen seated opposite him in the horse-car, begins conversation with her companion.

Her face is gentle, her whole mien refined,--but, her voice! She talks loudly and laughs constantly.

One beautiful woman whom I have met,--wealthy and well-educated, always reminds me of a peacock.

You doubtless have seen and heard peafowls often enough to understand the comparison.