By this, I mean do a person's body language and hand gestures as they speak manifest in a consistent and observable way? I'm a person who speaks with my hands very much; if I'm not moving my hands while I talk, I feel as if I'm not explaining things all the way. Are the hand gestures that I'm using as I speak as uniform as the words I would use to describe something?
There's a lot of research on this---co-speech gestures convey part of the message, but convey different information than the speech they accompany. They are definitely language and culture specific, so for example a person's gestures change when they learn an L2. Google “co-speech gesture” especially as related to second language learning, or work by David McNeil, Adam Kendon, or Susan Goldin-Meadow, eg Hearing Gesture; how our hands help us think. Harvard. 2003.
At university I did a research project using Labov's methodology to test if Cospeech Gestures would qualify as sociolinguistic variables. You would have to concede that spoken language has a visual component, but given that they proved to be a perfect textbook example. Still have that paper, on a floppy disk.
I asked myself the same question in 2011 and simply began to observe. Extending this idea to account for internal thought as well, I noticed some patterns. I am currently presenting my idea in a college mathematical modeling course. Here is a diagram I designed (I have most of the body filled out as well)