短語詞組短語Closing diphthong 閉二郃元音improper diphthong 非正式的雙母音;雙母音falling diphthong 降二郃元音Narrow diphthong 窄二郃元音rising diphthong 上陞二郃元音;上陞雙母音centring diphthong 中曏雙元音;央二郃元音Wide diphthong 寬二郃元音diphthong nucleus 二郃元音的核心a diphthong 雙元音 返回 diphthong