The Nelson Mandela Foundation has sent its condolences on the passing away of Professor Keorapetse William Kgositsile.
Kgositsile, 79, passed away at Milpark Hospital in Johannesburg on Wednesday afternoon.
"It is with heavy hearts that the trustees and staff of the Nelson Mandela Foundation heard of the passing of Ntate Keorapetse William Kgositsile. Our thoughts are with his family, friends and comrades at this most difficult time.
"His many accomplishments as an activist, author and intellectual are recorded indelibly in South Africa's public record. He was a trusted presence in almost every process designed by progressive formations in our country post-1990 to imagine the 'post-apartheid'," the foundation said in a statement.
The Mandela Foundation worked with him on a number of projects.
"We will remember him as much for his analyses as for his humour and his willingness to hold up a mirror rather than argue for a particular position. We will miss him. We have lost a friend. South Africa has lost a patriot. Hamba kahle Bra Willie," said Foundation Chief Executive Sello Hatang.
"His phone call was the first one I received after the announcement of my appointment back in 2013. His words of encouragement and wisdom then have stayed with me."
Rest in peace Bra Willie
The Pan South African Language Board (PanSALB) has also sent condolences on the passing of Kgositsile.
"This is indeed a great loss not only to the arts and language fraternity, but also to the entire country.
"Bra Willie, as he was affectionately known, was not only a political activist but also a cadre of the language movement, who largely and positively contributed to the promotion, preservation and protection of languages, through arts," the PanSALB said.
In 2008, Professor Kgositsile was awarded the national Order of Ikhamanga Silver (OIS) for excellent achievements in the field of literature and using these exceptional talents to expose the evils of the system of apartheid to the world.
"PanSALB would like to extend its sincere sympathy to his family and society at large in these trying times.
"The country has indeed been robbed off a literary giant. His positive work will remain active with us in spirit and may his soul rest in peace," PanSALB said.