This is the first of two thematically arranged volumes with papers that were presented at the "World Conference of Pluricentric Languages and their non-dominant Varieties" (WCPCL). It comprises papers about 20 PCLs and 14 NDVs around the world. The second volume encompasses a further 17 papers about the pluricentricity of Portuguese and Spanish. The conference was held at the University of Graz (Austria) on July 8th-11th 2015. The papers fall into five categories: (1) Theoretical aspects of pluricentricity and the description of variation; (2) Different types of pluricentricity in differing environments; (3) African pluricentric languages and non-dominant varieties; (4) The pluricentricity of Arabic and Asian languages; (5) The pluricentricity of European languages inside Europe (Austrian German, Bosnian/Serbian/Croatian, Hungarian, Belgium Dutch, French, Greek, Swedish, Russian).