Speech articulator movements recorded from facing talkers using two electromagnetic articulometer systems simultaneously

Two 3D electromagnetic articulometer (EMA) systems, the Carstens AG500 and Northern Digital WAVE, have been used simultaneously without mutual interference to record the speech articulator movements of two talkers facing one another two meters apart. A series of benchmark tests evaluating the stability of fixed distances between sensors attached to a rotating rigid body was first conducted to determine whether the two systems could operate independently, with results showing no significant effect of dual operation on either system. In the experiment proper, two native speakers of American English participated as subjects. Sensors were glued to three points on the tongue, the upper and lower incisors, lips, and left and right mastoid processes for each subject. Independent audio tracks were recorded using separate directional microphones, which were used to align the kinematic data from both subjects during post-processing. Data collected were of two types: extended spontaneous conversation, and repeated incongruent word sequences (e.g., talker one produced "cop top..."; talker two "top cop..."). Both talkers show strong positive correlations between speech rate (in syllables/sec) and head movement. The word sequences also show error and rate effects related to mutual entrainment.