Léopold Leau (1868-1943) was a French mathematician, primarily known for his many well-documented ties to international auxiliary languages.
The Delegation for the Adoption of an International Auxiliary Language was founded on January 7, 1901 on Leau's initiative. He co-wrote with Prof. Louis Couturat the monumental Histoire de la Langue Universelle (1903) and its supplement Les Nouvelles Langues Internationales (1907).
Along with his collaborator, Louis Couturat, Leau appears as a character in Joseph Skibell's 2010 novel, A Curable Romantic.