Here is a thing.
1. The final consonant 'ㅅ'('ㅆ')
1.1. 'ㅅ' + a vowel ☞ 'ㅅ'/s/ sound shifted to the vowel
<table width="89" border="1" cellspacing="0" cellpadding="0"> <tbody> <tr> <td width="28">ㅎ
</td> <td width="28">ㅐ
</td> <td width="28">ㅇ
</td> <td width="28">ㅓ
</td> <td width="28">ㅇ
</td> </tr> <tr> <td colspan="2" width="55">ㅆ
</td> <td colspan="2" width="55"></td> <td width="28">
ㅛ
</td> </tr> </tbody> </table> <table width="89" border="1" cellspacing="0" cellpadding="0"> <tbody> <tr> <td width="28">ㅎ
</td> <td width="28">ㅐ
</td> <td width="28">ㅆ
</td> <td width="28">ㅓ
</td> <td width="28">ㅇ
</td> </tr> <tr> <td colspan="2" width="55"></td> <td colspan="2" width="55">
</td> <td width="28">
ㅛ
</td> </tr> </tbody> </table>ㅆ + o = x + ㅆ, 해써요/hae-sseo-yo/, 어 ☞ 써
1.2 'ㅅ' + a consonant ☞ 'ㅅ' sound makes the consonant stronger
ㅎ
</td> <td width="28">ㅐ
</td> <td width="28">ㄷ
</td> <td width="28">ㅏ
</td> </tr> <tr> <td colspan="2" width="55">ㅆ
</td> <td colspan="2" width="55"></td> </tr> </tbody> </table> <table width="61" border="1" cellspacing="0" cellpadding="0"> <tbody> <tr> <td width="28">
ㅎ
</td> <td width="28">ㅐ
</td> <td width="28">ㄸ
</td> <td width="28">ㅏ
</td> </tr> <tr> <td colspan="2" width="55">ㄷ
</td> <td colspan="2" width="55"></td> </tr> </tbody> </table>
ㅆ + ㄷ = /ㄷ/ + ㄸ, 핻따/hat-tta/, 다 ☞ 따
2. 'ㄹ' sound
2.1. words or syllables end with the final consonant 'ㄹ' ☞ sounds like /l/
글/geul/, 일요일/i-ryo-il/
2.2. 'ㄹ' + a vowel ☞ sounds like /r/
라디오 ☞ ㄹ+ㅏ(vowel) ☞/ra/
2.3. 'ㄹ' + 'ㄹ' ☞ sounds like /l/
걸리다 ☞ 'ㄹ' in 걸 + 'ㄹ' in 리 ☞ /geol li da/
You don't need to memorize all of the rules because when you pronounce each syllable exactly and make it fast enough, all are yours.^^'
\^o^/
I will explain ㅅ or ㅆ as in 받침.
1. When 받침 ㅅ or ㅆ meets ㄷ (잇다/있다), you pronounce it as [읻따]. You do NOT prounce it as [읻타], which is close to a T sound. When I say it really fast though, I say it close to [이따].
i.e. 웃다 (to smile) --> [욷따]
씻다 (to wash) --> [씯따]
있다 (to exist) --> [읻따]
갔다 (went) --> [갇따]
2. When 받침 ㅆ meets ㅇ (있어), then you pronounce it as [읻써], which is close to an S sound as in Sunny. Again, when I say it fast, I pronounce it as [이써].
i.e. 있어요 (there is) --> [읻써요]
했어요 (did) --> [핻써요]
This youtube video shows you how to prounce double consonants: http://www.youtube.com/watch?v=D9pR-mem_o4
