Xul Solar

"Xul Solar was the adopted name of Oscar Agustín Alejandro Schulz Solari (born December 14, 1887 – April 9, 1963), Argentine painter, sculptor, writer, and inventor of imaginary languages." He was also a friend of Borges. On his invented languages (from Wikipedia):

He invented two fully elaborated imaginary languages, symbols from which figure in his paintings, and was also an exponent of duodecimal mathematics. He said of himself "I am maestro of a writing no one reads yet." One of his invented languages was called "Neo Criollo", a poetic fusion of Portuguese and Spanish, which he reportedly would frequently use as a spoken language in talking to people. He also invented a "Pan Lingua", which aspired to be a world language linking mathematics, music, astrology and the visual arts, an idea reminiscent of Hermann Hesse's "glass bead game". Indeed, games were a particular interest of his, including his own invented version of chess, or more precisely "non-chess".

See also:

Alejandro Xul Solar

Xul Solar Museum

Xul Solar on Language as Unity

Do you know Xul Solar?

Borges and Xul Solar

"Borges’s Cosmic Ally" By LARRY ROHTER, The New York Times, April 18, 2013.