Biology subjects

Ranacher, P.

Publications and source records attributed to Ranacher, P..

4 recordsLinked to original sources

bioRxiv2024

Oldest attested languages in the Near East reveal deep transformations in the distribution of linguistic features

It is an unresolved question to what extent the current frequency distributions of linguistic features inform us about what is representative of the language faculty and does not instead result from historical contingencies. We probe this question by leveraging unique data from the oldest attested languages, those preserved through writing from up to 5,000 years ago in the Ancient Near East. We examine 70 grammatical features for which there is sufficient evidence in the available records. After controlling for relatedness we find robust deviations of two of the oldest languages, Hurrian and Sumerian from both the ancient languages and the modern distribution. The spatial and temporal placement of these two languages reveal a divergent distribution of features in the region in prehistory, suggesting massive transformations of the linguistic distributions in the past few millennia. This challenges inferences about general characteristics of language based on modern distributions.

evolutionary biology↗

bioRxiv2021

Contact-tracing in cultural evolution: a Bayesian mixture model to detect geographic areas of language contact

When speakers of two or more languages interact, they are likely to influence each other: contact leaves traces in the linguistic record, which in turn can reveal geographic areas of past human interaction and migration. However the complex, multi-dimensional nature of contact has hindered the development of a rigorous methodology for detecting its traces. Specifically, other factors may contribute to similarities between languages. Inheritance (a property is passed from an ancestor to several descendant languages), and universal preference (a property is universally preferred), may both overshadow contact signals. How can we find geographic contact areas in language data, while accounting for the confounding effects of inheritance and universal preference? We present sBayes, an algorithm for Bayesian clustering in the presence of confounding effects. The algorithm learns which similarities in a set of features are better accounted for by confounders, and which are due to contact effects. Contact areas are free to take any shape or size, but an explicit geographic prior ensures their spatial coherence. We test the clustering method on simulated data and apply it in two case studies to reveal language contact in South America and the Balkans. Our results are supported by --mostly qualitative-- findings from previous studies. While we focus on the specific problem of language contact, the method can also be used to uncover other traces of shared history in cultural evolution, and more generally, to reveal latent spatial clusters in the presence of confounders.

evolutionary biology↗

bioRxiv2020

Can Bayesian phylogeography reconstruct migrations and expansions in human history?

Bayesian phylogeography aims to reconstruct migrations in evolutionary processes. This methodological framework has been used for the reconstruction of homelands and historical expansions of various language families, but its reliability for language diversification research has remained unclear. We contribute to this discussion with a simulation study where we distinguish two types of spatial processes: migration and expansion. By migration we denote long-distance movement of whole populations, leaving their previous habitat empty. Expansions are small-scale movements of speakers or inclusions of new speakers into the language community, cumulatively contributing to a gradual spread into new territories. We simulate migrations, in the form of directional random walks, and expansions, in the form of a grid-based region-growing process. We run both simulation scenarios with varying degrees of directional trends and evaluate the performance of state-of-the-art phylogeographic methods. Our results show that phylogeography fails to reconstruct migrations, but works surprisingly well on expansions, even under severe directional trends. We demonstrate that migrations and expansions have typical phylogenetic and spatial patterns, which in the one case inhibit and in the other facilitate phylogeographic reconstruction. Furthermore, we propose descriptive statistics to identify whether a real sample of languages (Bantu), their relationship and spatial distribution, better fits a migration or an expansion scenario. Bringing together the results of the simulation study and theoretical arguments, we make recommendations for judging the adequacy of phylogeographic models to reconstruct the spatial evolution of languages.

evolutionary biology↗

bioRxiv2019

Exploring deep-time relationships between cultural and genetic evolution in Northeast Asia

Culture evolves in ways that are analogous to, but distinct from, genomes. Previous studies examined similarities between cultural variation and genetic variation (population history) at small scales within language families, but few studies empirically investigated such parallels across language families using diverse cultural data. We report an analysis comparing culture and genomes from in and around Northeast Asia spanning 11 language families. We extract and summarize the variation in language (grammar, phonology, lexicon), music (song structure, performance style), and genomes (genome-wide SNPs) and test for correlations. We find that grammatical structure correlates with population history. Recent contact and shared descent fail to explain the signal, suggesting relationships that arose before the formation of current families. Our results suggest that grammar might be a cultural indicator of population history, while also demonstrating differences among cultural and genetic relationships that highlight the complex nature of human history.

evolutionary biology↗