One of the quickest ways a good writer can embarrass themselves is to poorly render an accent.
Struggling to speak English as a second language is a narratively interesting and culturally relevant experience, but also tricky to render well in printed English. It is one hell of a needle to thread. You have to focus on how the world infantilizes a person for speaking sub-standard English, without infantilizing the person.
When successful, I think you can show a great richness of character by how someone butts up against the limitations of their language. When you fail though you end up writing the Wardine Be Cry chapter of Infinite Jest.
