Programmed behaviour strictly rule-like or arbitrary
A new use of language poses a dilemma for a machine: either it treats the new usage as a case that falls under existing rules or it takes a blind stab at interpretation and updates its rule base. In either case, it fails to behave like a human.
In confronting a new use of language, machines face a dilemma: either, the new usage must be treated as a case that falls under existing rules (in which case rules covering all cases must be built beforehand), or the machine must take a blind stab at interpretation and update its rule base (in which case the machine is behaving in an arbitrary, and hence non human, fashion.
In either case, the machine is not like a human. A native speaker, by constrast, is embedded in the context of human life, which allows him or her to make sense of utterances in a non-rule like yet non-arbitrary way.