Western Romance languages are one of the two subdivisions of a proposed subdivision of the Romance languages based on the La Spezia–Rimini line. They include the Gallo-Romance and Iberian-Romance branches as well as northern Italian. The subdivision is based solely on the use of the "s" for pluralization and the weakening of some consonants, but that makes the categorization highly problematic because there is much higher lexical similarity between all dialects of Italian and French than between French and Spanish. There is also much higher morphological similarity between Spanish and Italian dialects than between Italian and French.