Think how often you say to yourself, "If only I hadn't said that," or something like "When I saw the look on her face, I knew that what I said had hurt her feelings." Wrong speech causes us many problems. We lie and then get caught in it; we say something nasty about a co-worker and get him into trouble; we speak inconsiderately and offend a client or friend; we spend a whole day in meaningless chatter and get nothing clone.

These bad habits of speech are not new. The Buddha considered the practice of Skillful Speech so essential to one's personal and spiritual development that he gave it its own step on the path to happiness. Skillful Speech, the Buddha told us, has four qualities: It is always truthful. It is uplifting, not malicious or unkind. It is gentle, not crude or harsh. It is moderate, not useless or meaningless.

A person who is known for gentle and beautiful speech, the Buddha explained, will quickly be trusted and respected. Such a person enjoys a calm and peaceful state of mind and is able to interact with others lovingly. Have you noticed, for instance, that people tend to speak to us as they have heard us speak? If we are known to exaggerate or to lie, others find it easier to lie to us. If we habitually malign others, people find it easier to speak harshly of us. The converse is also true. If we are known for truthfulness, our words are more readily believed. If we have a reputation for discretion, others find it harder to spread gossip about us. If our speech is always kind and gentle, others feel embarrassed to swear or speak crudely in our presence.

Skillful Speech
~by Bhante Gunaratana
Source: http://www.dharmanet.org/