This study tests whether individuals vocally align toward emotionally expressive prosody produced by two types of interlocutors: a human and a voice-activated artificially intelligent (voice-AI) assistant. Participants completed a word shadowing experiment of interjections (e.g., “Awesome”) produced in emotionally neutral and expressive prosodies by both a human voice and a voice generated by a voice-AI system (Amazon's Alexa). Results show increases in participants’ word duration, mean f0, and f0 variation in response to emotional expressiveness, consistent with increased alignment toward a general ‘positive-emotional’ speech style. Small differences in emotional alignment by talker category (human vs. voice-AI) parallel the acoustic differences in the model talkers’ productions, suggesting that participants are mirroring the acoustics they hear. The similar responses to emotion in both a human and voice-AI talker support accounts of unmediated emotional alignment, as well as computer personification: people apply emotionally-mediated behaviors to both types of interlocutors. While there were small differences in magnitude by participant gender, the overall patterns were similar for women and men, supporting a nuanced picture of emotional vocal alignment.

The current study investigates phonetic imitation of multiple acoustic features of pre-nasal /æ/ in California English. There is a great deal of cross-speaker heterogeneity: Many speakers show a raised /æN/ variant, in tandem with a backing and lowering of /æC/ (i.e., “split” short-a nasal system). This innovative split can also be realized with enhanced coarticulatory acoustic features on the pre-nasal allophone, namely extensive vowel nasality and increased diphthongization over the vowel duration. The present study compares phonetic imitation of three model talkers who produce distinct pre-nasal /æ/ variants: 1) a non-split talker who also does not produce enhanced nasal coarticulation and diphthongization, 2) a talker who produced the split, with a raised pre-nasal /æ/, but does not produce enhanced nasal coarticulation and diphthongization, and 3) a talker who produces both a pre-nasal /æ/ that is both raised and hyper-nasalized and heavily diphthongized. Participants who shadowed these model talkers could also be categorized as being advanced or conservative in their baseline productions. Results show that imitators who were more advanced in the sound change were more likely to imitate both vowel positioning and nasalization patterns of the conservative model talkers. Only diphthongization patterns of the most advanced model talker were imitated by the advanced participants. The results are discussed in terms of the multidimensionality of phonological contrast, theoretical proposals about phonetic imitation, and models of sound change and propagation.