You might be interested in this interview which came out just yesterday [1] about techniques for detecting people by the way they walk (apparently, throughpressure point patterns in a digital footprint) with (IIRC) 99.6% precision.
Regional identification through manners and/or phonology goes back to the concept of a shibboleth [2]. This is used rather wonderfully as a turning point in many stories (without spoiling too much, I should mention that Tarantino pulled this off nicely in one of his films).