Two letters in the bottom slot

Korean allows two consonants in the bottom slot. Your mouth cannot make two unreleased seals at once, so in isolation only one of the two comes out. Which one is fixed per cluster, and there is a rough pattern: the one that survives is usually the one you can hold.

Cluster	Sound that comes out	Example
ㄳ	[k̚]	몫 — a share
ㄵ	[n]	앉다 — to sit
ㄶ	[n]	많다 — to be many
ㄺ	[k̚]	닭 — chicken
ㄻ	[m]	삶 — life
ㄼ	[l]	넓다 — to be wide
ㄽ	[l]	외곬 — a single path
ㄾ	[l]	훑다 — to strip, to scan
ㄿ	[p̚]	읊다 — to recite
ㅀ	[l]	싫다 — to dislike
ㅄ	[p̚]	값 — price

When a vowel follows, both come back

The reason a cluster loses a letter is purely mechanical: there is nowhere to put the second consonant. Give it somewhere to go — a following packet whose first slot is the silent circle — and it goes there, and you say both.

• 값gap→값이gapsi[갑씨]

  On its own, only the first survives. Add a vowel and the second one moves into the next packet.

• 닭dak→닭이dalgi[달기]

  Same mechanism: the ㄱ has a vowel to attach to now.

• 앉다anda→앉아anja[안자]

  And the same again.

• 읽다ikda→읽어ilgeo[일거]

  Compare with 읽고, where no vowel follows.