tetraphthong

例句：

1. 1.She pronounced the word "tetraphthong" perfectly.
   她完美地发音了“四合音”。
2. 2.The teacher explained the concept of tetraphthong to his students.
   老师向学生解释了四合音的概念。
3. 3.In Chinese, the character for "tetraphthong" is written as "四合音".
   在中文中，“四合音”的字是“四合音”。