sentences:  It entered usage in the early-to-mid 20th century, and was originally coined by Isaac Schapera around 1930.It entered wider usage from the 1960s, based on the proposal of a "Khoisan" language family by Joseph Greenberg.The name "San" in anthropological usage is a back-formation from the compound and began to replace "Bushmen" from the 1970s onward (see San people#Names).