Can a linguistic serial founder effect originating in Africa explain the worldwide phonemic cline?
It has been proposed that a serial founder effect could have caused the present observed pattern of global phonemic diversity. Here we present a model that simulates the human range expansion out of Africa and the subsequent spatial linguistic dynamics until today. It does not assume copying errors, Darwinian competition, reduced contrastive possibilities or any other specific linguistic mechanism. We show that the decrease of linguistic diversity with distance (from the presumed origin of the expansion) arises under three assumptions, previously introduced by other authors: (i) an accumulation rate for phonemes; (ii) small phonemic inventories for the languages spoken before the out-of-Africa dispersal; (iii) an increase in the phonemic accumulation rate with the number of speakers per unit area. Numerical simulations show that the predictions of the model agree with the observed decrease of linguistic diversity with increasing distance from the most likely origin of the out-of-Africa dispersal. Thus, the proposal that a serial founder effect could have caused the present observed pattern of global phonemic diversity is viable, if three strong assumptions are satisfied.
Complex Systems Laboratory, University of Girona, Ma. Aurèlia Capmany 61, 17071 Girona, Catalonia, Spain Catalan Institution for Research and Advanced Studies (ICREA), Lluís Companys 23, 08010 Barcelona, Catalonia, Spain joaquim.fort@udg.edu.
Joaquim
http://orcid.org/0000-0003-2647-8558
J
Fort
Complex Systems Laboratory, University of Girona, Ma. Aurèlia Capmany 61, 17071 Girona, Catalonia, Spain.
Joaquim
http://orcid.org/0000-0002-8590-2155
J
Pérez-Losada
D000349:Africa; D006801:Humans; D008037:Linguistics
founder effect; front propagation; phonemic diversity; random walks