Complex sentence: Authorship issues concerning Martin Luther King, Jr. center around claims of plagiarism and fall into two general categories: one is his academic research papers (including his doctoral dissertation), and the other is his speeches.
Split into simpler sentences: Authorship issues concerning Martin Luther King, Jr. center around claims of Martin Luther King, Jr. having committed plagiarism. These issues fall into two general categories: one is his academic research papers (including his doctoral dissertation), and the other is his speeches.