1. Department of Linguistic and Cultural Evolution, Max Planck Institute for Evolutionary Anthropology , Deutscher Platz 6, Leipzig 04103 , Germany
2. Institutionen för lingvistik och filologi , Box 635, Uppsala University, 751 26 Uppsala , Sweden
3. School of Biological Sciences, The University of Auckland , Private Bag 92019, Auckland Mail Center, Auckland 1142 , New Zealand
4. School of Psychology, The University of Auckland, Auckland , Private Bag 92019, Auckland Mail Center, Auckland 1142 , New Zealand
5. Chair of Multilingual Computational Linguistics, University of Passau , Dr.-Hans-Kapfingerstr. 14d, 94032 Passau , Germany