Freaks chat line
Maybe some mechanical sound effects could convey the robotic nature of the machine writing the words, and perhaps the syntax should be less human in some ways, to lower expectations.
Sure, the first time a user tries Siri or Alexa or whatever Google's voice assistant is called (it really needs a name, IMO, to avoid inheriting everything the word "Google" stands for), they may ask something ridiculous or snarky.
Unfortunately, the seamless polish of the UI isn't matched by the capabilities of chatbots today, most of which are just dumb trees.
On the other hand, none of the voice assistants to date sounds close to replicating the natural way a human speaks.
These voice assistants may have more human timbre, but the stiff elocution, the mispronunciations, the frequent mistakes in comprehension, all quickly inform the user that what they are dealing with is something of quite limited intelligence.
The affordances draw palpable, if invisible, boundaries in the user's mind, and they quickly realize the low ROI on trying anything other than what is likely to be in the hard-coded response tree.