Globally, songs and instrumental melodies are slower and higher and use more stable pitches than speech: A Registered Report

Abstract

What, if any, similarities and differences between song and speech are consistent across cultures? Both song and speech are found in all known human societies and are argued to share evolutionary roots and cognitive resources, yet no studies have compared similarities and differences between song and speech across languages on a global scale. We will compare sets of matched song/speech recordings produced by our 81 coauthors whose 1st/heritage languages span 23 language families. Each recording set consists of singing, recited lyrics, and spoken description, plus an optional instrumental version of the sung melody to allow us to capture a “musi-linguistic continuum” from instrumental music to naturalistic speech. Our literature review and pilot analysis using five audio recording sets (by speakers of Japanese, English, Farsi, Yoruba, and Marathi) led us to make six predictions for confirmatory analysis comparing song vs. spoken descriptions: three consistent differences and three consistent similarities. For differences, we predict that: 1) songs will have higher pitch than speech, 2) songs will be slower than speech, and 3) songs will have more stable pitch than speech. For similarities, we predict that 4) pitch interval size, 5) timbral brightness, and 6) pitch declination will be similar for song and speech. Because our opportunistic language sample (approximately half are Indo-European languages) and unusual design involving coauthors as participants (approximately 1/5 of coauthors had some awareness of our hypotheses when we recorded our singing/speaking) could affect our results, we will include robustness analyses to ensure our conclusions are robust to these biases, should they exist. Other features (e.g., rhythmic isochronicity, loudness) and comparisons involving instrumental melodies and recited lyrics will be investigated through post-hoc exploratory analyses. Our sample size of n=80 people providing sung/spoken recordings already exceeds the required number of recordings (i.e. 60) to achieve 95% power with the alpha level of 0.05 for the hypothesis testing of the selected six features. Our study will provide diverse cross-linguistic empirical evidence regarding the existence of cross-cultural regularities in song and speech, shed light on factors shaping humanity’s two universal vocal communication forms, and provide rich cross-cultural data to generate new hypotheses and inform future analyses of other factors (e.g., functional context, sex, age, musical/linguistic experience) that may shape global musical and linguistic diversity.

The effect of musical training and language background on vocal imitation of pitch in speech and song.

“…No main effects or interactions were significant for either dependent variable (all p s > .25, all η p 2 s < .005). This may be surprising in light of other results showing higher pitch height for song and speech and more unstable pitch for speech than song (e.g., Ozaki et al, accepted in principle). However, these null effects do follow from two important considerations.…”

Cultural evolution of music and language

“…In summary, we need more comprehensive parallel analyses of musical/linguistic evolution that might help shed light on their potential distinct features, evolutionary origins, and/or coevolution (cf. Ozaki et al 2022 andPassmore et al 2022). The terms music and language encompass various forms and in some cases the boundary is not obvious (e.g.…”

“…Those similarities and differences are potential cultural traits that emerged through the evolutionary pressures specific to music-like vocal communication and language-like vocal communication. Ozaki et al (2022) reviewed the past song-speech comparison studies and proposed 6 features potentially demonstrating cross-cultural similarities and differences between song and speech, which are pitch height, temporal rate, and pitch stability for the differences and pitch interval, timbral brightness, and pitch declination for the similarities. Although these predictions are largely consistent with the previous studies comparing the acoustic signals of music and language using the data sampled from multiple languages (e.g.…”

Global musical diversity is largely independent of linguistic and genetic histories

“…However, future analyses sampling music, language, and genes from the same population at the same time may be able to examine possible sampling biases more comprehensively (cf. Hilton et al, 2022;and Ozaki et al, 2022 for examples of direct comparison of music and language recorded from the same individuals in diverse societies).…”

“…S11) indicates that our current findings of broad independence between musical and linguistic/genetic histories are robust to specific sampling decisions regarding the populations or variables included in the current analyses. Future analyses comparing broader ranges of musical/linguistic features (e.g., grammatical features (Matsumae et al, 2021;Skirgård et al, 2022); direct acoustic comparison of sung/spoken audio (Albouy et al, 2023;Ozaki et al, 2022) may help to understand the mechanisms underlying the separation.…”