“…Two types of roles have been investigated in different literatures: formal/functional roles, defined from the conversation type, e.g., anchorman/guests in Broadcast data [3,6,5] or professional roles in meetings [7,8], and social roles [12,13,14,15] related to how speakers interact between them. The literature on the first has mainly focused on the use of lexical and structural features while the literature on the second has mainly made use of nonlexical information (prosody and turn-taking statistics).…”