Pronunciation: Nasalization & Lateralization

When a stop final consonant (ㄱ, ㄷ, ㅂ sounds) is followed by ㄱ, ㄷ, ㅂ, ㅅ, or ㅈ, that following consonant becomes its tense (double) counterpart: ㄱ→ㄲ, ㄷ→ㄸ, ㅂ→ㅃ, ㅅ→ㅆ, ㅈ→ㅉ. The spelling never changes — only the sound tenses. Example: 학교 is written with ㄱ but pronounced [학꾜].

When ㅎ meets ㄱ, ㄷ, ㅂ, or ㅈ (in either order — ㅎ before or after), they merge into a single aspirated consonant: ㄱ+ㅎ→ㅋ, ㄷ+ㅎ→ㅌ, ㅂ+ㅎ→ㅍ, ㅈ+ㅎ→ㅊ. This works whether ㅎ is the final consonant or the initial of the next syllable. Example: 축하 → [추카], 좋다 → [조타].

When the final consonant ㄷ or ㅌ is followed by the vowel 이 (or 히), the sound shifts to a palatal: ㄷ+이→[지], ㅌ+이→[치], and ㄷ+히→[치]. Your tongue moves to the roof of the mouth. This only happens across a morpheme boundary (stem + particle/ending), not within a single root. Example: 굳이 → [구지], 같이 → [가치].