In Korean, the sounds 'k' and 'g' aren't much differenciated... Infact, 'ㄱ' is used for the sounds of both 'g' and 'k'... Whereas, 'ㅋ' is specifically for 'k'. These things do happen when the languages change... Korean doesn't have any sound similar to about 7-8 English alphabets. But, it has its own set which is diverse in its own. Hope you found it useful...