diff --git a/scripts/geodata/polygons/language_polys.py b/scripts/geodata/polygons/language_polys.py
index 6dfe3c85..e41b8adf 100644
--- a/scripts/geodata/polygons/language_polys.py
+++ b/scripts/geodata/polygons/language_polys.py
@@ -105,7 +105,7 @@ class LanguagePolygonIndex(RTreePolygonIndex):
                 if poly_type == 'Polygon':
                     poly = Polygon(rec['geometry']['coordinates'][0])
                     index.index_polygon(i, poly)
-                    poly = self.simplify_polygon(poly)
+                    poly = index.simplify_polygon(poly)
                     index.add_polygon(poly, dict(rec['properties']))
                 elif poly_type == 'MultiPolygon':
                     polys = []
@@ -114,7 +114,7 @@ class LanguagePolygonIndex(RTreePolygonIndex):
                         polys.append(poly)
                         index.index_polygon(i, poly)
 
-                    multi_poly = self.simplify_polygon(MultiPolygon(polys))
+                    multi_poly = index.simplify_polygon(MultiPolygon(polys))
                     index.add_polygon(multi_poly, dict(rec['properties']))
                 else:
                     continue