Starting memoir concerns are most often about these kinds of things - about what to tell, what not to tell. They belies a misunderstanding common in our culture - memoirs are "tell-alls" and what we tell is the hardest part. Will I get sued? Will my mother die? Questions like this are about content.
Content is important, don't get me wrong. Certainly Wild would not have been as strong a seller if her mother hadn't died (to be crude) and Eat Pray Love is leveraged on Gilbert's divorce (again, not to be crude). If those women had chosen to not write about these key aspects of their personal struggles because of fear over libel or dishonor, they would not have written the books at all.
However, what is more important is not what is written, but how it is written.
You will hear this again and again in all sorts of ways - show don't tell, your voice is what makes it work, and more. I think describing it as a what-to-how progression is best, though. Once you get to the point where you can focus more on how to write it than what to write - and not just how to write it to honor or avoid liability, but how to tell the story best - then you are on the right track.
A great example of this is Chronology of Water by Lidia Yuknavitch, a perennial favorite of mine. In a recent meeting of my Read and Write community, my students, having read the book ahead of time, were repeatedly blown away most by how Yuknavitch writes. Yes, she writes about sex, about drugs, about alcohol. She writes about sexual abuse, dropping out of school repeatedly, and violence. But the book is more than the sum of those parts - it is her voice, her language, her style - it is the literature of the book that blows it out of the park.
She has a PhD in literature, and she knows her stuff. She pulls back the curtain to tell us, in fact, that there is more than one way to tell a story. Frequently she alternates chapters in which she tells the bulk of a particular story in straightforward narrative: x happened, then y, then z, with a chapter in which, as she quotes Dickinson in the interview at the end of the book, "the language goes strange." In these more lyrical chapters, she drops all structure - paragraphs, punctuation, perspective - and just lets the sensorial experience rip. She describes this experience during the book in a lyrical way:
Have endless patterns and repetitions accompanying your thoughtlessness, as if to say let go of that other more linear story, with its beginning, middle, and end, with its transcendent end, let go, we are the poem, we have come miles of life, we have survived this far to tell you, go on, go on.None of what she does it a gimmick. It has to do with fully conveying the experience through words. She often presents the same story - for instance, hitting another car head-on when completely wasted - in both lyrical and narrative style. Often using lines like "Wait. That's a lie," as a transition, Yuknavitch gives us both the narrative information we are used to using to get along, with the full feeling of being there, in her body. It's a powerful pairing.
With the exception of memoirs or autobiographies actually billing themselves as tell-all, most memoir relies on fictional devices like this - changed perspectives, metaphor, lyrical writing and more - in order to deliver to the reader the closest experience possible to the truth of that moment. Yuknavitch speaks to this in the interview in the book. She didn't want to write another addiction or incest memoir. She is tired of this genre based on what they are talking about. Her book defies content categorization, cannot be referred to as a ____ memoir. Rather, what people typically say about it points to the how: it's a lyrical memoir, an intense memoir, a structure-breaking memoir.
If you are writing personal essay or memoir, figuring what language will support your content best takes time. There's no one formula. You can start by imitating or immersing yourself in the style of someone like Yuknavitch, or another favorite. Try it on, not to ape it, but to see what fits. Maybe breaking the fourth wall - speaking directly to the reader - helps you be totally honest. Maybe talking about yourself in second person (you), as Yuknavitch does in one chapter, followed by telling us she is doing this to control our perceptions, is the way to go.
Play. Explore. When you get caught up in the whats - should I include that thing about my sister? - try some hows: How could I write about that incident so it is mine, not hers, so I respect her but also tell my truth? Keep trying, keep telling.