Origin of Hangul
Ledyard holds that the Koreans adopted five core consonant letters from ’Phags-pa, namely ㄱ "g" , ㄷ "d" , ㅂ "b" , ㅈ "j" , and ㄹ "l" . These were the consonants basic to Chinese phonology, rather than the graphically simplest letters (ㄱ "g" , ㄴ "n" , ㅁ "m" , and ㅅ "s" ) taken as the starting point by the "Haerye." A sixth letter, the null initial ㅇ, was invented by Sejong. The rest of the consonants were developed through featural derivation from these six, essentially as described in the "Haerye"; a resemblance to speech organs was an additional motivating factor in selecting the shapes of both the basic letters and their derivatives.
Kim Tu-bong
After graduating from Bosungkobo (Bosung College) in 1908, Kim Tu-bong worked closely with a Linguistic professor from Bosungkobo named Ju Sigyeong who was at that time beginning his work in the study of Hangul for which his name would later be known for as he would dedicate his life to bring it about (the Korean script made by King Sae Jeong during the 15th century). He also worked as a teacher. In 1916 he spent a majority of his time working on compiling MalMooe, the first Korean dictionary.