重じゅう母ぼ音いんじゅうぼいんMeanings1noundiphthonglinguisticsLinguistics term for a complex vowel sound that begins with one vowel and glides into another within the same syllable. Often contrasted with 二重母音.See also: 二重母音英えい語ごの「time」の「i」は重じゅう母ぼ音いんです。The 'i' in English 'time' is a diphthong.