To explain the pronunciation change of 'ㅂ, ㄹ, ㄱ, and ㄷ', It changes according to the consonant of the letter coming after. You can find the similar rule of 'ng' sound in Japanese. The rule in Korean is loose compared to that in Japanese. 'ㄱ' or 'ㅋ' is pronounced as 'ㅇ'(ng), when the latter word is started by 'ㄴ,ㄹ,ㅁ' 작년(the last year) - jang nyeon 독립(independence) - dong lib 박막(thin film) - bang mak 'ㄷ' or 'ㅌ' is pronounced as 'ㅇ'(ng), when the latter word is started by 'ㄴ,ㄹ,ㅁ' 'ㅂ' or 'ㅍ' is pronounced as 'ㅁ'(m), when the latter word is started by 'ㄴ,ㄹ,ㅁ' 'ㄱ' is pronounced as 'ㅋ'(K) when the latter started by 'ㅎ', 박하(mind) - bag ha - ba ka(but bag ka could be OK) 'ㄷ' is pronounced as 'ㅊ'(ch), when the latter started by '히' 닫히다(to be closed) - dad hi da - da chi da 'ㅂ' is pronounced as 'ㅍ'(p), when the latter started by 'ㅎ' 잡히다(to be caught) - jab hi da - ja pi da 'ㅂ' is pronounced as 'ㅁ'(m), when the latter started by 'ㅇ', and the latter is a compound word. the 'ㅇ' sounds 'ㄴ'(n). 잡일(chores) - jam nil, in other case excluding the exception above, it's pronounced as itself, hope this helped. peace,

There is a rule to write and pronounce the korean words. Here, it is the link for you. You will learn the Korean alphabets and the construction of the words. http://rki.kbs.co.kr/learn_korean/lessons/english/eng_p01.htm

Lol I just posted the same question..very confusing..if you work it out let me know please!! Will let you know if I get some good awnsers too!