Having a second voice repeat after you

Like the title suggests, I have a voice repeat after me sometimes. This first started happening some time ago(I’m not sure, but I believe it to be about a month), that whenever I listened to binaurale beats(theta waves) for any workings, be it evocations, invocations or just meditations, I would start to hear a second (a bit deeper and rougher voice) repeating what I said just a moment after I said it after getting a bit deeper into the theta gamma sync. I was a bit weirded out by it, but didn’t think to much of it. Some time later I said this incantation, which I found in the incantaions thread.

A day after doing it, while laughing during a conversation, I and the person I had a conversation with, both could hear it happening audible. This happened only once, but it was pretty wierd at the time. Now, (after not having done any working lately) it happens a lot faster when using binaurale beats.
Any help in finding out what this means would be greatly appreciated.