Quantifying the spatial pattern of dialect words spreading from a central population.

Area of Science:

• Linguistics
• Sociolinguistics
• Computational Social Science

Background:

• Geographically distant groups share dialect words without interaction, suggesting cultural influence.
• Concentric dialect distributions, like in Japan, may stem from innovations at a central location (e.g., Kyoto) and outward diffusion.

Purpose of the Study:

• To develop and test a model of linguistic diffusion to explain concentric dialect patterns.
• To quantify the distribution of linguistic variants originating from a central population.
• To investigate the role of novelty bias and transmission direction in linguistic spread.

Main Methods:

• Developed a mathematical model for linguistic diffusion within population networks.
• Analyzed equilibrium distributions of word ages on idealized and realistic (Japanese prefectures) networks.
• Compared model predictions with observed dialect patterns.

Main Results:

• The model successfully replicated observed concentric dialect patterns.
• A center-periphery social structure adequately explains these patterns.
• Novelty bias is not always necessary; directional transmission bias is crucial.
• Population size differences between prefectures had minimal impact on transmission.

Conclusions:

• Linguistic diffusion models can explain dialect distribution patterns.
• Center-periphery dynamics are key to understanding concentric dialect formations.
• Transmission directionality, rather than novelty, is a more significant factor in dialect spread.