2 sentences

1. 这种乐器是通过空气振动而发声的。

   zhè zhǒng yuè​qì shì tōng​guò kōng​qì zhèn​dòng ér fā​shēng de.

   This instrument produces sound through air vibration.

   Source: Dong Chinese Dictionary

2. 在这个社会问题上，我们需要更多的人出来发声。

   zài zhè​gè shè​huì wèn​tí shàng, wǒ​men xū​yào gèng duō de rén chu​lai fā​shēng.

   On this social issue, we need more people to speak out.

   Source: Dong Chinese Dictionary