(CNN) There's no standard way survivors talk about sexual assault. It isn't always a police phone call and a rape kit; sometimes it's years of silence. Sometimes it trickles out, little by little, and then all at once; like a dam that swells and breaks and floods.

Part of it is fear: Will I be believed, these women and men think. Part of it is doubt, sown by social mores that seem eager to excuse the inexcusable: Was it something I should just accept?

When they do talk, sometimes years later, a question reflexively arises. It's a question that was posed, more or less, by the President of the United States , to a woman who alleges a current Supreme Court nominee held her down at a high school party and tried to assault her: Why didn't you speak up earlier?

In response, people on Twitter have been sharing their reasons for not speaking up about their own assaults.

They're afraid of repercussions

It's something victims grapple with a lot: the anguish and terror about retaliation. It's one reason that Christine Blasey Ford -- the woman who accused Judge Brett Kavanaugh of sexual misconduct -- said she kept silent for years

#WhyIDidntReport because I was 11 yrs old, in my second foster home, and she was a model foster parent and he was her son, so it would have been my word against his. And I was afraid I'd end up in an even worse foster home if I was removed. — TraCee 🎃🎈🔪💀 (@TraCee_tr) September 21, 2018

#WhyIDidntReport Two of his fraternity brothers showed up at my dorm room the next day and threatened to kill me if I told. — Marley (@drcmarley) September 21, 2018

They are made to feel it's their fault

It happens over and over again: Victims say that when they do speak up, they are met with judgment and not support. "What were you wearing?" they're asked. "How much were you drinking?"

I was 16yo the first time I was raped. I didn't understand consent, rape, and thought it was my fault. For this and many reasons are #WhyIDidntReport — Alison Turkos (@alisonturkos) September 21, 2018

I was 17. I was embarrassed that I froze, that I let it happen. He was my boss #WhyIDidntReport — jawniferojawny (@jenniferaphael) September 21, 2018

I felt like because I was heavily under the Influence it was somehow my fault and Burden. #WhyIDidntReport — Liz Katz (@LizKatzOfficial) September 21, 2018

They're told to dismiss it

Many times, a victim will confide in someone, only to be told not to pursue it any further.

#WhyIDidntReport my first assault: because he was a coworker and friend with my then-boyfriend, who told me I shouldn't "make it a thing" and "disrupt the culture at work." After all, he was sorry. He felt guilty. The assault wasn't that bad. I should be thankful. — Danielle Campoamor (@DCampoamor) September 21, 2018

#WhyIDidntReport It was 1969, and even though my stepbrother was asst DA for LA, he said that a trial would be worse for me than for the boys who had gang-raped me. I got pregnant as a result, and abortion was illegal then. I never told anyone else about it for 20 years. — valeriestone (@valeriestone) September 21, 2018

#WhyIDidntReport years later when i told my mom she said "i'm sorry you feel that you were molested" (she feels incredibly guilty about this now and has apologized) — Julia Wilde (@Julia_SCI) September 21, 2018

They are often the ones who were blamed

The perpetrator -- and many times, the victim's own family members -- make them feel like they "deserved it."

Because he was my Uncle and when I tried to say something I was grounded and whipped. I felt dirt because he made me feel like I wanted it. And I didnt want people to think I was incestuous. (13 years) #WhyIDidntReport — Wendywitch (@Wendywitch1990) September 21, 2018

They're afraid they would be asked for more evidence

The attack is traumatic enough. Victims are often asked to relive it by recounting it in excruciating detail.

The #WhyIDidntReport hashtag is so important. I don't want to take away from women's stories, but this happened to me as well. I didn't report because a minister told me I didn't have enough evidence to prove anything and it would just cause a scandal. I was 18. This is common — Garrard Conley (@gayrodcon) September 21, 2018

Because I knew I would be expected to answer questions, and potentially even be contacted by my abuser, and I didn't want to talk about it any further or ever interact with him again. #whyididntreport — Danielle Ingrid Anais Tcholakian (@danielleiat) September 21, 2018

They're afraid no one will believe them

The attack, in many cases, is a family member or a person with a certain standing in the community. Speaking out means pitting the victim's word against the perpetrators.

#WhyIDidntReport. Because my biological father tried to rape me when I was 14. He was a sociopath and a covert narcissistic personality disordered person and pretended to be a perfect parent in public. He was a church deacon. No one would have believed me and I knew it. — Jamie B (@jambie61) September 21, 2018

They're afraid people will find out

Sometimes, victims feel it's easier to keep it to themselves. The guilt, fear, shame and confusion is paralyzing,

I was humiliated. I knew everyone would find out. I was afraid it would ruin my professional reputation before I had even started. I was afraid they would not believe me and let him hold my grade back. I was afraid they would not let me graduate from law school. #WhyIDidntReport — Amee KavaNOPE Vanderpool (@girlsreallyrule) September 21, 2018

They want to forget

Author Kurt Eichenwald painfully recounts how he was raped after an epileptic seizure and how he wanted nothing more than to just forget it. "Because," he said, "thinking meant feeling, and feeling terrified me."

My police report after assault was more traumatizing than the assault itself. You don't report because nothing about the institutions you've grow up around messages safety. Instead it's willingly putting yourself up for doubt and judgement at the most terrible moment of your life — Karla L. Monterroso (@karlitaliliana) September 21, 2018

I was nine years old.



He was also a minor.



I struggled immensely with thoughts that I had wanted or welcomed it.



I just wanted it to go away and live like it had never happened.



For several years, I did.



It was 20 years before I was able to say so publicly.#whyididntreport — Eric Atcheson, Member of an All-Adult Generation (@RevEricAtcheson) September 21, 2018

Actress Alyssa Milano added her voice to the movement with an op-ed , saying it took her 30 years to talk about her personal experience with assault.

"For me, speaking up meant reliving one of the worst moments of my life," she wrote. "It meant recognizing my attacker's existence when I wanted nothing more than to forget that he was allowed to walk on this earth at all. This is what every survivor goes through."