ISONYMY AND ISOLATION BY DISTANCE IN GERMANY

The isonymy structure of Germany was studied using the surname distrib utions of 5,150,310 private telephone users selected from 39,000,000 u sers registered in a 1996 commercial CD-ROM, which contains all teleph one users in the country. The users were distributed in 106 towns sele cted on a geographic basis. Germany was subdivided into 50 adjacent re ctangles, each 115 x 80 km, and at least the largest town in the recta ngle was selected for study; the private telephone users in that distr ict were downloaded from the CD-ROM and included in the analysis, The shortest distance between nearest neighbor towns was 10.7 km (Travemun de and Lubeck), and the largest distance was 69.8 km (Meppen and Osnab ruck). The number of different surnames found in the whole analysis wa s 462,526. Lasker's distance, the negative value of the logarithm of i sonymy between localities, was found to be linearly and significantly correlated with geographic distance (r = 0.51 +/- 0.010). A dendrogram was built with the matrix of isonymy distances, using UPGMA. This met hod separates the German towns into two main clusters, one in the sout hern half of the country and the other in the northern half, Within ea ch cluster small subclusters with specific geographic distributions co uld be delimited. The two main clusters correspond fairly well to the north-south division of German sublanguages (Nieder- and Mitteldeutsch in the north vs. Frankisch-Alemannisch in the south). The other clust ers are related to minor sublanguages. Comparisons with the results of a previous analysis of Switzerland's structure are given, From the pr esent analysis isolation by distance emerges clearly, although it is l ess strong than in Switzerland and indicates that Germany has a fairly homogeneous isonymy structure, The random component of inbreeding est imated from isonymy indicates that eastern Germany is on average more inbred than western Germany.