Influence of voice properties on vowel perception depends on speaker context

Different speakers produce the same intended vowel with very different physical properties. Fundamental frequency (F₀) and formant frequencies (F_F), the two main parameters that discriminate between voices, also influence vowel perception. While it has been shown that listeners comprehend speech more accurately if they are familiar with a talker's voice, it is still unclear how such prior information is used when decoding the speech stream. In three online experiments, we examined the influence of speaker context via F₀ and F_F shifts on the perception of /o/-/u/ vowel contrasts. Participants perceived vowels from an /o/-/u/ continuum shifted toward /u/ when F₀ was lowered or F_F increased relative to the original speaker's voice and vice versa. This shift was reduced when the speakers were presented in a block-wise context compared to random order. Conversely, the original base voice was perceived to be shifted toward /u/ when presented in the context of a low F₀ or high F_F speaker, compared to a shift toward /o/ with high F₀ or low F_F speaker context. These findings demonstrate that that F₀ and F_F jointly influence vowel perception in speaker context.