Yup, this is true. When you are in REM (during the time you actually dream), your body is paralyzed. Have you ever woke up and thought your dream actually happened or had the thoughts and memories vividly linger for a little bit? That is probably happening to you while you are in the paralysis part. The whispering and stuff is probably the dream partially continuing as your body hasn't realized you have woken up yet.
Star