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Spatial Structure of Evolutionary Models of Dialects in Contact.

Murawaki Y - PLoS ONE (2015)

Bottom Line: We found that a group of dialects can be considered tree-like even if it has not evolved in a temporally tree-like manner but has a temporally invariant, spatially tree-like structure.In addition, the simulation experiments appear to reproduce unnatural results observed in reconstructed trees for real data.These results motivate further investigation into the spatial structure of the evolutionary history of dialect lexicons as well as other cultural characteristics.

View Article: PubMed Central - PubMed

Affiliation: Department of Advanced Information Technology, Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan.

ABSTRACT
Phylogenetic models, originally developed to demonstrate evolutionary biology, have been applied to a wide range of cultural data including natural language lexicons, manuscripts, folktales, material cultures, and religions. A fundamental question regarding the application of phylogenetic inference is whether trees are an appropriate approximation of cultural evolutionary history. Their validity in cultural applications has been scrutinized, particularly with respect to the lexicons of dialects in contact. Phylogenetic models organize evolutionary data into a series of branching events through time. However, branching events are typically not included in dialectological studies to interpret the distributions of lexical terms. Instead, dialectologists have offered spatial interpretations to represent lexical data. For example, new lexical items that emerge in a politico-cultural center are likely to spread to peripheries, but not vice versa. To explore the question of the tree model's validity, we present a simple simulation model in which dialects form a spatial network and share lexical items through contact rather than through common ancestors. We input several network topologies to the model to generate synthetic data. We then analyze the synthesized data using conventional phylogenetic techniques. We found that a group of dialects can be considered tree-like even if it has not evolved in a temporally tree-like manner but has a temporally invariant, spatially tree-like structure. In addition, the simulation experiments appear to reproduce unnatural results observed in reconstructed trees for real data. These results motivate further investigation into the spatial structure of the evolutionary history of dialect lexicons as well as other cultural characteristics.

No MeSH data available.


Related in: MedlinePlus

Maximum clade credibility tree of Japonic dialects.The horizontal axis gives the time before present. The number attached to each branch is the posterior sample support ratio for the corresponding clade. The data were taken from Table s3 of Lee and Hasegawa [27]. We tried to replicate the original experiments, but there are minor differences between Lee and Hasegawa’s and ours probably because of the random nature of the sampling process and unexplained model configurations. These variances do not affect the overall results or our discussion.
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pone.0134335.g001: Maximum clade credibility tree of Japonic dialects.The horizontal axis gives the time before present. The number attached to each branch is the posterior sample support ratio for the corresponding clade. The data were taken from Table s3 of Lee and Hasegawa [27]. We tried to replicate the original experiments, but there are minor differences between Lee and Hasegawa’s and ours probably because of the random nature of the sampling process and unexplained model configurations. These variances do not affect the overall results or our discussion.

Mentions: To highlight the obstacles to applying tree models to dialects in contact, we examine a reconstructed tree for Japonic dialects. We exclude Ryukyuan dialects and show the mainland portion of the tree in Fig 1 (hereafter the mainland portion of Japonic is simply referred to as Japanese). Among several drawbacks of the resulting tree, it is particularly inconsistent that modern Japanese dialects are interpreted as having been formed by a series of branching events in the past 500 years. These branching events are unlikely to be explained by historical events like mass migrations. If these purported branching events do not correspond to key events in historic times, it seems too optimistic to expect that they correspond in prehistoric times. However, the date of the first branching event was associated with the arrival of the first farmers to the Japanese archipelago [27]. It is almost certain that all of the data points considered (except the northernmost point of Hokkaido) had Japanese speakers in the past 500 years without massive population flows. In this example, it is clear that it is more consistent to keep all of the data points intact in the recent past than to merge them into common ancestors.


Spatial Structure of Evolutionary Models of Dialects in Contact.

Murawaki Y - PLoS ONE (2015)

Maximum clade credibility tree of Japonic dialects.The horizontal axis gives the time before present. The number attached to each branch is the posterior sample support ratio for the corresponding clade. The data were taken from Table s3 of Lee and Hasegawa [27]. We tried to replicate the original experiments, but there are minor differences between Lee and Hasegawa’s and ours probably because of the random nature of the sampling process and unexplained model configurations. These variances do not affect the overall results or our discussion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519344&req=5

pone.0134335.g001: Maximum clade credibility tree of Japonic dialects.The horizontal axis gives the time before present. The number attached to each branch is the posterior sample support ratio for the corresponding clade. The data were taken from Table s3 of Lee and Hasegawa [27]. We tried to replicate the original experiments, but there are minor differences between Lee and Hasegawa’s and ours probably because of the random nature of the sampling process and unexplained model configurations. These variances do not affect the overall results or our discussion.
Mentions: To highlight the obstacles to applying tree models to dialects in contact, we examine a reconstructed tree for Japonic dialects. We exclude Ryukyuan dialects and show the mainland portion of the tree in Fig 1 (hereafter the mainland portion of Japonic is simply referred to as Japanese). Among several drawbacks of the resulting tree, it is particularly inconsistent that modern Japanese dialects are interpreted as having been formed by a series of branching events in the past 500 years. These branching events are unlikely to be explained by historical events like mass migrations. If these purported branching events do not correspond to key events in historic times, it seems too optimistic to expect that they correspond in prehistoric times. However, the date of the first branching event was associated with the arrival of the first farmers to the Japanese archipelago [27]. It is almost certain that all of the data points considered (except the northernmost point of Hokkaido) had Japanese speakers in the past 500 years without massive population flows. In this example, it is clear that it is more consistent to keep all of the data points intact in the recent past than to merge them into common ancestors.

Bottom Line: We found that a group of dialects can be considered tree-like even if it has not evolved in a temporally tree-like manner but has a temporally invariant, spatially tree-like structure.In addition, the simulation experiments appear to reproduce unnatural results observed in reconstructed trees for real data.These results motivate further investigation into the spatial structure of the evolutionary history of dialect lexicons as well as other cultural characteristics.

View Article: PubMed Central - PubMed

Affiliation: Department of Advanced Information Technology, Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan.

ABSTRACT
Phylogenetic models, originally developed to demonstrate evolutionary biology, have been applied to a wide range of cultural data including natural language lexicons, manuscripts, folktales, material cultures, and religions. A fundamental question regarding the application of phylogenetic inference is whether trees are an appropriate approximation of cultural evolutionary history. Their validity in cultural applications has been scrutinized, particularly with respect to the lexicons of dialects in contact. Phylogenetic models organize evolutionary data into a series of branching events through time. However, branching events are typically not included in dialectological studies to interpret the distributions of lexical terms. Instead, dialectologists have offered spatial interpretations to represent lexical data. For example, new lexical items that emerge in a politico-cultural center are likely to spread to peripheries, but not vice versa. To explore the question of the tree model's validity, we present a simple simulation model in which dialects form a spatial network and share lexical items through contact rather than through common ancestors. We input several network topologies to the model to generate synthetic data. We then analyze the synthesized data using conventional phylogenetic techniques. We found that a group of dialects can be considered tree-like even if it has not evolved in a temporally tree-like manner but has a temporally invariant, spatially tree-like structure. In addition, the simulation experiments appear to reproduce unnatural results observed in reconstructed trees for real data. These results motivate further investigation into the spatial structure of the evolutionary history of dialect lexicons as well as other cultural characteristics.

No MeSH data available.


Related in: MedlinePlus