C. F. (Charles Frederic) Hayes

Born on December 4, 1857, in Blackheath, London, he became known as an English Esperantist as well as a bookkeeper. He died on January 9, 1942.

He is chiefly associated with the English-Esperanto Dictionary, a reference work credited to C. F. Hayes and John Charles O'Connor. That dictionary helped make Esperanto more accessible to English speakers and remains the work most closely linked with his name.

Although surviving biographical detail appears limited, the record that does survive points to a practical-minded figure in the early Esperanto world: someone involved not just in ideas, but in the careful language work needed to support a growing international community.