What a person should do to comprehensively understand and accept diversity of language?

Introduction: understanding basic concepts

Standard American English

Language Variety

African American Vernacular English

...

Slang

Accent

Code Switching

Code Meshing

Further understanding: What is common language?

Core English+ people's dialects

Origin of dialect: people's diverse cultural background

Function of dialect: help distinguishing people's different cultural background

Factors that may determining a person's language

Family background

i.e. Amy Tan: Mother's tongue

i.e. Cisneros: Only Daughter

Another Language

Language of Nature: Kimmerer: Speaking of Nature