Robots or Agents - Neither Helps You More or Less During Second Language Acquisition Experimental Study on the Effects of Embodiment and Type of Speech Output on Evaluation and Alignment

When designing an artificial tutor, the question arises: should we opt for a virtual or a physical embodied conversational agent? With this work we contribute to the ongoing debate of whether, when and how virtual agents or robots provide more benefits to the user and conducted an experimental study on linguistic alignment processes in HCI in the context of second language acquisition. In our study (n = 130 non-native speakers) we explored the influence of design characteristics and investigated the influence of embodiment (virtual agent vs. robot vs. speech based interaction) and system voice (text-to-speech vs. prerecorded speech) on participants' perception of the system, their motivation, their lexical and syntactical alignment during interaction and their learning effect after the interaction. The variation of system characteristics had no influence on the evaluation of the system or participants' alignment behavior.