the only way i can describe it is an uncontrollable entity speaking like a snake, gives you a feeling of numbness and lack of control during dreams
you named it , it’s part of the dream
in my opinion it sounds like something your subconscious put into the dream to explain any sleep paralysis (numbness) creeping into the dream and your becoming slightly aware that you aren’t as alert and your usual freewill isn’t quite there (through the sleep becoming lighter and so your level of consciousness rising?)
It sounds like parseltongue to me… lol !
Does this occur when you’re actually dreaming? Or performing WILD? Or waking up?