Observe This Sunnah.

[Abu Hafsat]

As-Salaam alaikum, 

The Sunnah of the Prophet, Sallallahu alaihi Wasallam, regarding speech is based on the following hadith- Abu Huraira, may Allah be pleased with him, reported that the Prophet, Sallallahu alaihi Wasallam, said :-

"Whoever believes in Allah and the Last Day, let him say what is good or remain silent" (Bukhari). 

The default of one's speech is that one remains silent and does not speak unless one is sure that his speech will be good. If one is unsure of it will be good or bad, then one remains silent. So the Sunnah is that one remains silent until one is sure. 

Some of the sins related to one's tongue are : ghiba (backbiting), namima (gossiping), suna (showing off), royal with speech, kaziba (lying), iftikhar (boasting to others, making claims).. 

We should keep this in mind and note accordingly.