音调符号

例句：

1. 1. The phonetic symbols are used to represent the sounds of the language.
   音调符号用来表示语言的音。
2. 2. The phonetic symbols were introduced to help people pronounce words more accurately.
   引入音调符号是为了帮助人们更准确地发音。
3. 3.The phonetic symbols are essential for teaching children how to read and write in a foreign language.
   音调符号对于教授孩子如何阅读和写作一门外语至关重要。