satyam priya-hitam cha yat
van-mayam tapa ucyate" (Bhagwat Gita: Chapter Seventeen verse 15)
"Sri Krishna said: O Arjuna, Austerity of speech consists in speaking words that are truthful, pleasing, beneficial, and not agitating to others, and also in regularly reciting Vedic literature."
So before you speak anything, just think twice -Is it necessary? Is it true? Is it kind? Will it hurt someone? After examining all these aspects, speak such words which shall be beneficial to others & shall not hurt anyone in anyway. Otherwise, as is said that, "Speech is Silver & Silence is Gold", practice this, as there are times when silence has the loudest voice.