Scientists aren’t exactly sure why sleep talking occurs during stage 3 sleep, but it may relate to how “different areas of the brain communicate really well with each other” during this particular sleep stage, reports Mic.

You might be genetically predisposed to this phenomenon, since it tends to run in families, Neubauer says. Stress and anxiety could also make you more likely to sleep talk, since they could disturb your sleep, “lowering the threshold for that kind of expression to occur.” In rare cases, certain medications that increase the duration and intensity of stage 3 sleep might also increase your chances of sleep talking, Scharf says.