Great point. I've tried sifting through the interviews for clues to any possible truths..my list is short. I don't know what you call this when a person speaks differently when they lie vs when they're truthful. But from what I've observed Jessica reverts to speaking like a teenager when she's fabricating..do you know what i mean. I can point it out in the various interview clips. And VDK has no less than three tell tale signs of a liar when he speaks.
I think it is called a "tell" or an "indicator".
A "tell" like in poker is a change in a player's behavior or demeanor.
When lying, there are certain "tells" or "indicators". Everyone is different and for some people they do give themselves away rather obviously where with others it can be difficult to tell if they are lying. When I am fibbing with my wife I always give myself away because I start to smile or giggle. I cant help myself.
I found a link and I think it describes what you are talking about. Here is part of it and Bolded the part that you may be talking about for Jessica:
"
If you are wondering if someone is lying, look for verbal changes like:
more pauses
slower speech
stuttering
elevated pitch
Facial expressions
Watching a person’s face when he or she is talking can tell you a lot about whether the person is lying, since it is difficult to control facial expressions and the emotions behind them.
A few facial signs to watch for that may suggest that someone is lying:
expressions that don’t match the words that are being said (saying “I love you” with an angry scowl)
expressions that don’t match the timing of the words (saying “Wonderful!” and not smiling until a few seconds later)
Here are some other facial signs that a person might be lying:
hiding emotions (showing no emotion)
masking real emotions with false ones
showing emotion when none is felt
Experts also recommend focusing on the eyes and forehead, which are harder areas of the face to control than the mouth and cheeks. It’s in these areas where honest emotion can be more easily detected.
"
http://sciencenetlinks.com/student-teacher-sheets/all-about-lying-honest/