Different speakers produce the same intended vowel with very different physical properties. Fundamental frequency ( F0) and formant frequencies ( FF), 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 FF 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 FF 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 FF speaker, compared to a shift toward /o/ with high F0 or low FF speaker context. These findings demonstrate that that F0 and FF jointly influence vowel perception in speaker context.

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Speech perception is heavily influenced by our expectations about what will be said. In this review, we discuss the potential of multivariate analysis as a tool to understand the neural mechanisms underlying predictive processes in speech perception. Multivariate pattern analysis might allow us to quantify the amount of information carried by the spatial or temporal patterns of brain activity ranging from the phonetic form of speech, over syllable identity to its semantic content. We suggest that using multivariate techniques to measuring informational content across the hierarchically organised speech-sensitive brain areas might enable us to specify the mechanisms by which prior knowledge and sensory speech signals are combined. Specifically, this approach might allow us to decode how different priors, e.g., about a speaker’s voice or about the topic of the current conversation, are represented at different processing stages and how thereupon the incoming speech signal is differently represented.