Jean Leó Leonard got his PhD. From Université de Provence in 1991 on empirical sociolinguistics,. He was initially trained as a Finno-Ugrist, on Finnic languages, especially Finnish and Estonian, at Inalco. Since 1991 he has carried on fieldwork and theoretical research on several languages and dialects including Mesoamerican languages (Mayan, Otomanguean, Totonaco-Tepehua and Huave). He has been developing interdisciplinary research for dialectology and Complexity Theory since 2010. He is currently holding the position of full professor of Linguistic Typology and Linguistic Diversity at Paris-Sorbonne University.