I recently received a telemarketing robocall that had a convincingly human voice.

It did polite social chitchat quite well.

But there were a few tell-tale signs: the bot would never interrupt or overlap my talking. It would always wait until I finished speaking to parse my speech, and its pauses were very consistent and slightly longer than what was natural.

When I asked it if it were a robot, it replied, "(giggle) why, do I sound like a robot?"

When I threw it a few unconventional questions, it quickly became clear that there was a script.