Quoted from
http://www.koreanwikiproject.com/wiki/index.php?title=%EB%B0%9B%EC%B9%A8
1. Pronunciation: Consonant followed by a vowel
If a consonant in the final position is followed by a vowel, the consonant sound shifts over to the syllable with the vowel. The only sounds that don't shift over to the next syllable are ㅇ since it is impossible to begin a syllable with an "ng" sound and ㅎ becomes silent when followed by a vowel. Also when ㅌ is in the final position and followed by the vowel 이, the sound becomes 치, see ㅌ + 이. Similarly when ㄷ is in the final position and followed by the vowel 이, the sound becomes 지.
맞아 [마자] ㅈ sound shifts over to the next syllable
먹어 [머거] ㄱ sound shifts over to the next syllable
집에 [지베] ㅂ sound shifts over to the next syllable
좋아 [조아] ㅎ sound goes silent if followed by a vowel
놀아 [노라] ㄹ sound shifts over to the next syllable
필요 [피료] ㄹ sound shifts over to the next syllable
영어 [영어] The ㅇ 받침 sound does not shift over
한국어[한구거] ㄱ sound shifts over to the next syllable
같이 [가치] ㅌ + 이 = 치. See ㅌ + 이
굳이 [구지] ㄷ + 이 = 지. See ㄷ + 이
졸업 [조럽] ㄹ sound shifts over to the next syllable
십일 [시빌] ㅂ sound shifts over to the next syllable
중앙 [중앙] The ㅇ 받침 sound does not shift over
2. Pronunciation: Consonant not followed by a vowel
If a consonant is in the final position and it is not followed by a vowel (meaning it is the last syllable of the word or followed by another consonant), then it may have a different pronunciation. Notice from the table below that many characters share the same sound when in the 받침 position. Also note: ㅃ, ㄸ, and ㅉ can't appear in the final position.
ㄱ,ㄲ,ㅋ => ㄱ
먹다 [먹따]
부엌 [부억]
깎다 [깍따]
ㅂ,ㅍ => ㅂ
수업 [수업]
춥다 [춥따]
높다 [놉따]
ㄹ => ㄹ
ㅇ => ㅇ
ㄷ, ㅎ,ㅈ,ㅅ,ㅆ,ㅌ,ㅊ => ㅅ
옷 [옫]
곧 [곧]
찾다 [찯따]
있다 [읻따]
같다 [갇따]
꽃 [꼳]