Creepy Pastas and other creepy stories

Backwards

My girlfriend’s been talking in her sleep. I work late sometimes, and don’t get in until she’s already gone to bed. Now, she’s always talked in her sleep, but it’s only recently gotten weird. She lived in Russia for about ten years, so when she started speaking in a language that I didn’t understand I wasn’t all that worried. But the other day I got really curious as to what she was saying. I videotaped her rambling, and sent it to a friend of mine. I was more than surprised when he told me that she wasn’t speaking Russian at all. 

I asked her about it as soon as I read the reply, showing her the video. She was a bit upset that I’d taped her, but she couldn’t place the language either. She told me that she wasn’t having any weird dreams, so I brushed it off. That night I’d stayed late again, and had called her to let her know not to wait up. As soon as I stepped into the bedroom, I was super careful not to wake her up. I went through my routine of brushing my teeth, pissing, all that. By the time I settled into the bed, she’d started talking again. I couldn’t help it- I picked up my phone, and started recording again. Whatever she was saying, she was saying it over and over again. I stopped after about a minute. 
The next morning, I got bored and decided to mess around a bit with the recording. I slowed it down, speed it up, and did a lot of other stuff trying to figure out what exactly she was saying. Finally, I played it backwards. 

“I know what you did.” 
My heart stopped in my chest. This was what she had been saying last night. How long had she known? 

That night, when she started talking again, I reached over to the bedside table again and picked up the knife.