Initial sound rule

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Initial sound rule" – news · newspapers · books · scholar · JSTOR (May 2024) (Learn how and when to remove this message) The neutrality of this article is disputed. Relevant discussion may be found on the talk page. Please do not remove this message until conditions to do so are met. (June 2024) (Learn how and when to remove this message) (Learn how and when to remove this message)

Initial sound rule (Korean: 두음법칙; Hanja: 頭音法則; RR: dueum beopchik ) is series of changes to hangul, the writing system for the Korean language, made in South Korea to better reflect modern Korean phonology. The changes affect syllable-initial ㄹ r and ㄴ n sounds in Sino-Korean vocabulary under certain conditions. North Korea orthography does not recognize this rule, making it one of a number of North–South differences in the Korean language.