Iknow this for a fact, because when i was growing up, my mother’s “limited” english limited my perception of her. i was ashamed of her english. i believed that her english reflected the quality of what she had to say. that is, because she expressed them imperfectly her thoughts were imperfect. which phrase from the excerpt uses informal english?

The last sentence is very formal. It does not contain the first person pronoun (I or me) which is one of the marks of informal writing. Having given you the answer, may I say  that question is almost totally irrelevant. I do not mean that you are at fault for having asked it. You are only asking for an answer, and that was given.

What I really mean to say is that I hope you get to read more of Amy Tan's remarks about her mother's English. They are astonishing observations and should be required reading by every student taking English or American Literature.

Thank you for posting this question. I didn't there was more to Tan's essay about her mother's English that I didn't know about, and I'm glad to know there is more.

a question like this requires the excerpt to be included in order to answer the question.