Human voice pitch measures are robust across a variety of speech recordings: methodological and theoretical implications

Fundamental frequency ( f o ), perceived as voice pitch, is the most sexually dimorphic, perceptually salient and intensively studied voice parameter in human nonverbal communication. Thousands of studies have linked human f o to biological and social speaker traits and life outcomes, from reproductive to economic. Critically, researchers have used myriad speech stimuli to measure f o and infer its functional relevance, from individual vowels to longer bouts of spontaneous speech. Here, we acoustically analysed f o in nearly 1000 affectively neutral speech utterances (vowels, words, counting, greetings, read paragraphs and free spontaneous speech) produced by the same 154 men and women, aged 18–67, with two aims: first, to test the methodological validity of comparing f o measures from diverse speech stimuli, and second, to test the prediction that the vast inter-individual differences in habitual f o found between same-sex adults are preserved across speech types. Indeed, despite differences in linguistic content, duration, scripted or spontan­­eous production and within-individual variability, we show that 42–81% of inter-individual differences in f o can be explained between any two speech types. Beyond methodological implications, together with recent evidence that inter-individual differences in f o are remarkably stable across the lifespan and generalize to emotional speech and nonverbal vocalizations, our results further substantiate voice pitch as a robust and reliable biomarker in human communication.