In her story "Mother Tongue," Amy Tan describes her relationship with her mother, who speaks "broken" English. Essentially, Amy ending up changing her style of writing because of her mother, who changed Amy's perception of language. In the beginning of her life, Amy was always ashamed and embarrassed because of her mother; her mother, in speaking broken English, would often sound weird and not be understood by people in every day affairs. As an attempt to get away from this side of her heritage, Amy--once she becomes a writer--writes with great English and diction, and she uses a plethora of vocabulary. However, she soon realizes that she is being someone she is not; Amy eventually fully realizes her true relationship with her mother, and subsequently allows that newfound knowledge to affect her writing. Their relationship is one of wonderful love and comfort, one where they can speak broken English ("mother tongue") and have it mean something very special.
Essentially, Amy Tan becomes authentic and true to her roots; inspired by her mother, she begins to right so that the 'common man' can understand her.