What are the afflictions of the tongue that a Muslim must avoid?

The matter of the tongue is grave, and it is obligatory upon a Muslim to pay attention to what emanates from it; for a servant may enter Hellfire due to a word he pays no heed to. Among the major afflictions of the tongue are: uttering disbelief (kufr), reviling Allah and His Messenger, and mocking the religion. Also among its afflictions are: cursing and reviling a Muslim, slandering chaste women, backbiting and calumny, lying, breaking promises, divulging secrets, scoffing and slandering, speaking with a double tongue, engaging in falsehood, excessive praise, excessive joking, speaking about what does not concern one, and artificiality and excessive eloquence in speech.