He was as careful in his speech as in his actions. It goes without saying that he refrained from whatever was prohibited by the halachah.
For this we have Rabbi Israel [Salanter's] own testimony. Upon reproving one of his disciples for his words, Rabbi Israel [Salanter] remarked: "Insofar as evil gossip (lashon hara) is concerned, you cannot tell me, 'Remove a beam from between your eyes,' and, it seems, not with respect to idle chatter either."
But even in speech that is permitted, he avoided superfluous verbiage and would weigh and count his words to make them conform to standards of propriety and refinement. One of the scholars of the generation observed on a specific occasion: "Rabbi Israel [Salanter] does not squander words. Every sound or word that issues from his mouth is first considered and reflected on. He purifies them like a silver smelter and weighs them in a chemical balance." -- The Mussar Movement Volume 1, Part 2 page 197
Yaakov’s short letter is loaded with instructions regarding proper speech. Yaakov reminds us that we oughtn’t swear by anything, but let “yes” and “no” suffice (). He instructs us to not judge others with our words (-12). He warns us to not speak as if we know our future (-16). Yaakov speaks eloquently about the power of speech and the difficulty people have in controlling their tongues. He explains that one's mouth shouldn’t be able to both speak praise of God and evil against people – this is deep hypocrisy (3:1-12). In the beginning of his letter, Yaakov speaks of the value of silence:
“Come, my children, listen to me, and I will teach you to fear Hashem. Who is the man who desires life, to love each day and see only goodness in them? Let him then guard his tongue from speaking evil and his lips from speaking deceit. Turn away from evil and do what is good, desire peace and pursue it.” — Psalm 34
A famous Chasidic story illustrates the extent of the damage that Lashon HaRa can do: A man went about gossiping and telling malicious stories without restraint. Later, when he realized how much his tales had hurt people, and began to feel remorse. He went to the Rabbi seeking repentance, saying he would do anything he could to make amends. The Rabbi told the man, “Take a feather pillow, cut it open, and scatter the feathers into the wind.” The man thought this was a bizarre request, but it was simple enough, and so he did it. When he returned to inform the rabbi that the task was done, the Rabbi said, “Now, go and collect all the feathers and return them to the pillow.” Again, the man went to do as the rabbi had asked, but found that the feathers had blown far and wide, and he was unable to retrieve even a handful. He returned to the rabbi, ashamed to admit he was not able to gather the feathers, certain that he should never have released the feathers in the first place. Knowingly, the rabbi rebuked him, saying, “Your words are like the feathers: once they leave your mouth, you know not where they will go, and you can never retrieve them back again. It is always wiser to guard your tongue and keep your words to yourself.”
Shimon ben Gamliel said: I have grown up among the Sages all my days, yet I have never found anything better for a person than silence. Study [of Torah] is not the main thing, but the doing [of Torah] is. And all who speak too much bring on sin. —Avot 1:17
An encrypted cache of uncensored documents that WikiLeaks founder Julian Assange has circulated across the Internet may ensure that a huge array of secrets will be revealed even if the website is shut down or Assange is arrested. — online news 12/4/2010