Please Say/Whisper the Words out Loud
Lesson 1 - ABOUT people
We learned that lashon hora is speech that can cause another person degradation or shame. Another form of lashon hora is speech which may cause financial harm.
Lesson 2 - TO people
Of you cause someone pain or resentment by insulting them, they will tend to react with a polarity response, they will do the opposite of what you want. (Taken from The Power of Words, by Rabbi Zelig Pliskin, and Purity of Speech)