From 1862 to 1869 Effendi had studied the local language use and then proceeded to compile the book "Bayan-al-Din". Printed by the Turkish Ministry of Education in Istanbul, it is an interesting and significant part of South Africa's history, and serves as a valuable reference of the Afrikaans usage during that era in the Islamic neighbourhoods of Cape Town. It gives an invaluable insight into the use of Afrikaans in the so-called "Slams" (slang for Islamic) neighbourhoods of Cape Town in that period. It is also significant, since this community did not have Dutch as mother tongue and were therefore mostly unaffected by its orthography. As such this was the first substantial book ever written and published in Afrikaans, although written in a modified Arabic script where the diacritic signs are used to indicate the pronunciation of Afrikaans. It bears testimony to the slave origins of the language which was not accredited by the White Afrikaners, especially during the Apartheid Era.