Descartes to Mersenne on universal language, Ramón Llull

It is well known that Descartes is a pioneer in having provided inspiration for the universal language idea, in an era when the scientific revolution was accompanied by a philosophical revolution and the attempt to perfect human thought via the construction of logically ordered languages. An entry point for this literature can be found in my bibliography, with web links:

Philosophical and Universal Languages, 1600-1800, and Related Themes: Selected Bibliography

Descartes' key letter on the subject can be found in English translation on my web site:

Descartes to Mersenne, 20 November 1629 

It is also well known that the medieval mystic Ramón Llull was a pioneer of the ars combinatoria, which inspired the philosophical language program as well as modern developments in logical calculi. Descartes himself was not so charmed by him:

Descartes to Mersenne, 25 December 1639