In 1857 Soga returned to the Eastern Cape with his wife where they eventually founded the Emgwali Mission where Soga worked among his native Ngqika people. During their years in Emgwali the Soga's had eight children, one of whom was stillborn. Two of their sons - William Anderson Soga and John Henderson Soga - followed their father and were ordained as ministers and missionaries, and two of their daughters - Isabella McFarlane Soga and Francis Maria Anna Soga - were employed as teachers in mission. Kirkland Allan Soga, studied law at University of Glasgow and became the first black lawyer in South Africa, and a politician involved in the founding of the African National Congress. His fourth son was Jotello Festiri Soga, the first black veterinary surgeon in South Africa. The youngest daughter born just a year before Soga died, Jessie Margaret Soga became a classic contralto soloist and teacher studying in Milan and a licenciate of the Royal College of Music, London and a leading suffragist. Janet Soga returned to England for the births of all her children. Tiyo Soga suffered from poor health and it was during one of these bouts of sickness that he used his time to translate "Pilgrim's Progress" (U-Hambo Iom-Hambi) into his native Xhosa language. Soga's translation and adaptation of "Pilgrim's Progress" has been called "the most important literary influence in 19th century South Africa after the Bible." He also worked to translate the Christian gospels and served on the advisory board to revise the Xhosa Bible.