Original objective and subjective characterization of phonetic convergence

Individuals accommodate their communication behavior either by increasing similarity with their interlocutors (i.e. convergence) or on the contrary by increasing their differences (i.e. divergence). Speech accommodation has been observed at both linguistic and non linguistic levels. Several studies have been conducted on phonetic dimensions such as pitch, speech rate, loudness or dispersions of vocalic targets with various experimental paradigms ranging from close-shadows of prerecorded stimuli to more ecological face-to-face conversations. Multiple objective and subjective characterizations of phonetic convergence have been proposed. This paper discusses limitations of current proposals, notably in terms of top-down strategies that may be used by labelers and listeners when characterizing/perceiving the stimuli. We put forward and evaluate here two novel techniques: objective characterization by speaker recognition techniques and subjective characterization by a novel paradigm named "speaker switching". We will illustrate these techniques with stimuli collected during an original experimental paradigm called verbal dominoes (Lelong and Bailly, 2011), a speech game that can be played by several interlocutors and consisting in chaining rhyming words.