Korean is written in an alphabet called 한글 (Hangul), which was created in 1443 under King Sejong the Great. Hangul is widely admired for its logical design: the shapes of the letters are not arbitrary but were originally drawn to mirror the shape of the tongue and mouth as they produce each sound. The alphabet consists of 14 basic consonants — ㄱ ㄴ ㄷ ㄹ ㅁ ㅂ ㅅ ㅇ ㅈ ㅊ ㅋ ㅌ ㅍ ㅎ — and 10 basic vowels — ㅏ ㅑ ㅓ ㅕ ㅗ ㅛ ㅜ ㅠ ㅡ ㅣ. Together, these 24 letters form every syllable in the language. In addition, there are five tense or "double" consonants known as 쌍자음 (ssangjaum): ㄲ ㄸ ㅃ ㅆ ㅉ, which are stressed versions of ㄱ, ㄷ, ㅂ, ㅅ, and ㅈ.
Hangul letters are not written in a line the way English letters are. Instead, they are grouped into square syllable blocks, each containing an initial consonant, a vowel, and an optional final consonant. For example, the word 한글 is built from two blocks: 한 (ㅎ + ㅏ + ㄴ) and 글 (ㄱ + ㅡ + ㄹ). The final consonant at the bottom of a block is called 받침 (batchim). Some letters behave differently depending on their position: ㅇ is silent when it appears at the beginning of a syllable (where it acts as a placeholder before a vowel) but makes an "ng" sound when it serves as the batchim, as in the English word "sing." Other consonants, such as ㄱ and ㅂ, are pronounced somewhere between a hard and a soft sound — ㄱ resembles the "g" in "go," while ㅂ resembles the "b" in "bus," with the exact pronunciation shifting depending on what follows.