interlocutor (n.) Look up interlocutor at
1510s, "one who speaks in a dialogue or conversation," agent noun from Latin interlocut-, past participle stem of interloqui "speak between; interrupt," from inter- "between" (see inter-) + loqui "to speak" (see locution).

In minstrel shows, the name of a straight-man character (1870) who was the questioner of the end men. Related: Interlocutory. Fem. forms include interlocutress (1858), interlocutrix (1846), interlocutrice (1848).