1. It is assumed that Ancient Korean had features of pitch and duration as well as three suprasegmental phonemes. But the details are unknown to us. 2. Middle Korean(MK) has three suprasegmental phoneme(SSP)s and their features are: ◁표 삽입▷ (원문을 참조하세요) MK SSPs change by phonological obligatory rules as follows: (1) Ⅱ changes to Ⅰ at the second syllable or below. (2) θ changes to Ⅰ after Ⅰ or Ⅱ Polysyllabic words of MK have three SSP patterns: (1) θ-type : θ₁Ⅰ_0 (2) Ⅰ-type : Ⅰ₁ (3) Ⅱ-type : Ⅲ_0 3. Three SSPs of Kyungbuk dialect and relevant MK SSPs are: (1) O[-Long, +High] from θ of MK ex. k`och `flower` (2) U[-Long, -High] from Ⅰ of MK ex. phul`grass` (3) W[+Long, -High] from Ⅱ of MK ex. pyel `star` Phonological rules of SSP of Kyungbuk dialect: (1) W changes to U at the second syllable or below. (2) O changes to U after U or W. In polysyllabic words /O/ and /U/ have 2 phonetic allophones respectively. (1) phoneme /O/ has two allophones [O] and [o] (2) phoneme /U/ has two allophones [U] and [u] Phonetic rules for /O/ and /U/: (1) O changes to [o] before O. (2) U changes to [u] after O or at the third syllable or below. Kyungbuk dialect has three SSP patterns: (1) O-type : O₁U_0 (2) U-type : U₁ (3) W-type : WU_0