The line in the above excerpt from Amy Tan's "Mother Tongue" that shows that Tan changes her language depending on the audience is: “The talk was about my writing, my life, and my book, The Joy Luck Club, and it was going along well enough, until I remembered one major difference that made the whole talk sound wrong. My mother was in the room.”
It is foreshadowed that Susan is at a zenith, a highpoint in her life. This, however seems to be the last highpoint that she will ever be at, insinuating that the rest of her life was much more depressing and less exciting.