  Through proliferation on smartphones and smart speakers, intelligent personal
assistants (IPAs) have made speech a common interaction modality. Yet, due to
linguistic coverage and varying levels of functionality, many speakers engage
with IPAs using a non-native language. This may impact the mental workload and
pattern of language production displayed by non-native speakers. We present a
mixed-design experiment, wherein native (L1) and non-native (L2) English
speakers completed tasks with IPAs through smartphones and smart speakers. We
found significantly higher mental workload for L2 speakers during IPA
interactions. Contrary to our hypotheses, we found no significant differences
between L1 and L2 speakers in terms of number of turns, lexical complexity,
diversity, or lexical adaptation when encountering errors. These findings are
discussed in relation to language production and processing load increases for
L2 speakers in IPA interaction.

Human-Computer Interaction;Computation and Language