“I spend a great deal of my time thinking about the power of language—the way it can evoke an emotion, a visual image, a complex idea, or a simple truth.” 

The crux of Tan’s argument is that how one thinks about language and how one represents ideas is important. This introductory argument about the “power of language” is referential to the quality of Tan’s writing in “Mother Tongue” and to her larger point regarding different forms of English and writing for a specific audience. Later in the text Tan describes her mother’s ability to do all the things that she lists here: evoke emotion, describe vivid images, express complex ideas, and capture truth.

“Recently, I was made keenly aware of the different Englishes I do use.” 

Tan argues that there are different “Englishes.” There are formal Englishes, Englishes for different contexts (e.g., for the family, for out in public), and Englishes specific to people who speak languages other than English. Tan articulates her own understanding and awareness of the importance of these myriad Englishes as she develops her perspective in this essay.

“You should know that my mother’s expressive command of English belies how much she actually understands.” 

Although this quote speaks to a specific example of types of English, this is a critical underlying argument of Tan’s essay: that a person’s “expressive command” over English does not necessarily reflect their actual ability to understand or think in complex ways.