Through speech, we communicate linguistic messages – words and sentences – with one another. However, speech sounds also convey rich nonlinguistic and paralinguistic information, such as a speaker’s emotional states, attitudes, or social identity. Our lab investigates how speech functions as a medium for expressing such nonlinguistic cues, with particular interest in how vocal cues (e.g,. pitch, voice quality) shape listeners’ perceptions. By examining the acoustic-phonetic features of voices with various types of speaking styles, including those generated by AI, we aim to understand how listeners interpret these cues to form impressions about the speaker. This research deepens our understanding of speech communication within real-life contexts and informs the development of socially intelligent AI voices.