Right Speech is difficult. So in order to have Right Speech we have to develop our Wisdom Parami. We have to develop our Compassion/Lovingkindness Parami. We have to develop our Renunciation Parami - renunciation of unskillful speech. Sometimes this means letting go of some desires that cause us to have bad speech.
Right Speech is part of Morality. There are three factors of Morality in the Noble Eightfold Path (Right Speech, Right Action, Right Livelihood), so certainly Morality is needed. What is Right Speech? Refraining from gossip, that is repeating things that we don't know to be true, therefore it helps the Truthfulness Parami. Because if we hear something and we repeat it, but we don't know for ourselves that it is true, then we are hurting our Truthfulness Parami. Another aspect of Right Speech is refraining from harsh speech, hurtful speech, this is usually motivated by aversion. By looking into our aversion within ourselves, developing the Compassion/Lovingkindness, we try to refrain from hurtful speech, harsh speech.
The Truthfulness Parami is greatly helped in this development of Right Speech because a lot of what we feel is not actually true, it is just our perceptions of what is true. Idle chatter, useless speech, just going on and on, certainly if we have a lot of restlessness in the mind we may have a lot of idle speech, but that is not very useful. So considering this when we look at the Energy Parami and trying to develop a balanced energy rather than an energy that is excessive and always outward going. Equanimity is a great aid to Right Speech.
Right Speech, one of the most difficult, I think. That is why it is so helpful for everybody to stay quite in a silent retreat, then at least we get to look at the urges that come into our mind and start to transform these urges, transform these intentions. We get to practice to look at our thoughts, so that if we go back into normal life we have this practice, so we don't just blurt things out all the time.