4 sentences

1. 他背地里说了我不少坏话。

   tā bèi​dì​li shuō le wǒ bù​shǎo huài​huà.

   He said many bad things about me behind my back.

   Source: Dong Chinese Dictionary

2. 谁在说坏话？

   shéi zài shuō huài​huà?

   Who's saying bad things?

   Source: OpenSubtitles

3. 在别人背后说坏话是不道德的。

   zài bié​ren bèi​hòu shuō huài​huà shì bù​dào​dé de.

   It is immoral to speak ill of others behind their backs.

   Source: Dong Chinese Dictionary

4. 我小时候她常打电话说我妈妈的坏话。

   wǒ xiǎo​shí​hou tā cháng dǎ​diàn​huà shuō wǒ mā​ma de huài​huà.

   She used to call when I was little and say bad things about my mom.

   Source: OpenSubtitles