Complex sentence: His classification was for a time considered very bold and speculative, especially the proposal of a Nilo-Saharan language family, but is now generally accepted by African specialists and has been used as a basis for further work by other scholars.
Split into simpler sentences: His classification was for a time considered very bold and speculative, especially the proposal of a Nilo-Saharan language family. Now it is generally accepted by African specialists and has been used as a basis for further work by other scholars.