Naturally interacting robots must be able to understand natural human speech. As such, recent work has sought to allow robots to infer the intentions behind commonly used non-literal utterances such as indirect speech acts (ISAs). However, it is still unclear to what extent ISAs will actually be used in task-based human-robot dialogue, and to what extent robots could function without the ability to understand ISAs. In this paper, we present the results of a Wizard-of-Oz experiment that examined human ISA use in scenarios that did or did not have conventionalized social norms, and analyzed both ISA use and perceptions of robots when robots were or were not capable of understanding ISAs. Our results suggest that (1) ISAs are commonly used in task-based human-robot dialogues, even when robots show themselves unable to understand ISAs; (2) ISA use is more common in contexts with conventionalized social norms; and (3) a robot's inability to understand ISAs harms both the robot's task performance and human perception of the robot.

As the linguistic capabilities of interactive robots advance, it becomes increasingly important to understand how humans will instruct robots through natural language. What is more, with the increased use of teleoperated humanoid robots, it is important to recognize whether any differences between instructions given to humans and to robots are due to the physical embodiment or to the perceived autonomy of the instructee. In this paper, we present the results of a human-subject experiment in which participants interacted in a collaborative, task-based setting with both a human and a suit-based, teleoperated humanoid robot said to be either autonomous or teleoperated. Our results suggest that humans will use politeness strategies equally with human, autonomous robotic, and teleoperated robotic teammates, reinforcing recent findings that autonomous robots must comprehend and appropriately respond to human utterances that follow such strategies. Our results also suggest variations in how different teammates were perceived. Specifically, our results suggest that human-teleoperated robots were perceived as less intelligent than human teammates; a finding with serious implications for human-robot team dynamics.