The two TED presentations links that Donna has provided are good. They emphasize the negative aspects of bad speech.
What “y not” stated is true in general. One mostly comes across material that are not good or even harmful sometimes.
So, if one gets material from reliable sources, it is not a bad idea to look at them, if one has time. But most of this information is in Buddha Dhamma, and the “Moral Living and Fundamentals” section has posts on such topics.
Furthermore, it is important to understand that vaci sankhara is not just speech, but also includes conscious thoughts. One can be generating a lot of bad vaci sankhara without saying a single word: “Correct Meaning of Vacī Sankhāra“.