When we communicate with words we actually construct a reality. It is through language and concepts that we understand ourselves and the world around us. For example when we use words and concepts that communicate hatred, we construct a reality that is permeated by that hatred. Over time, we find others who replicate this hate speech and hateful ideas, eventually hateful actions will take place. Furthermore, if we pass on these hateful ideas to our children, to people we influence, we are creating terrible patterns for not only ourselves, but contributing to these patterns in innumerable other individuals. Now this hatred can multiply and over time we may have contributed to the creation of uncountable permutations of that hatred- which likely include violent actions. From a Buddhist perspective, we would have created terrible suffering for ourselves and others by having such hate speech.
Contrarily if we speak words of genuine tolerance and compassion, we actually can generate a field of generosity, and openness. Instead of seeking to tear someone else apart, we can try to appreciate the depth of their unique struggle in life. From this perspective, any speech we have crystallizes a reality. Furthermore speech itself is totally interconnected with our thoughts. Thoughts are nothing but speech that we engage with to ourselves, ie. inner dialogue. The more we say something, the more likely we are to think it. The more we think something, the more likely we are to say it. It is like a system, a feedback loop. From a Buddhist/karmic perspective this can either work against us (create more dis-satisfaction) or for us (release us from dis-satisfaction).
If we learn that this speech/thought system is always in play we can intervene on it. That is, we can choose to speak in ways that build others up, that reflect tolerance, and compassion. If we do this, then we are more likely to have tolerant and compassionate thoughts. If we have tolerant and compassionate thoughts, we are then more likely to have more tolerant and compassionate speech! The same goes for pride, envy, jealousy, hatred, greed... as well as humility, gratitude, love, generosity, compassion, joy, and serenity.
What do we do if we have "negative" thoughts? Does that mean we are destined to be evil or be dis-satisfied?
In short, no. This is what the Buddhist path, and other paths to awakening to love and compassion are all about. In these paths, instead of acting out these "negative" thoughts, we learn to transform them. Through the application of practices, teachings, perspectives we can start to transform our thoughts and our speech. In doing so, we start to construct a new reality.
From a Mahayana Buddhist perspective, such reconstruction involves the idea of our individual nature as being ultimately selfless. That is, conventionally speaking, we turn our entire lives into a project for self-preservation. We use all of our resources to defend this concept of our "self." We use greed, hate, envy, jealousy to defend this self, ensuring that we have to react incessantly; that way we can re-assure ourselves of our own self-importance, and self-existence. When we live in this state of constant reaction, we suffer immeasurably. Our vision becomes so focused on our self, our problems, our thoughts, our lives, our significance, our this, our that- and we overlook the simplicity, profundity, mysteriousness, and the bottomless depth of suffering that connects every being to one another.
From this perspective, using our speech kindly is just one drop in a bucket. But our drops have dye in them- the hateful ones too. One drop can spread the dye significantly in the bucket of water. As we refine our speech and our thoughts, our drops became more concentrated, our presence becomes clearer. We can recognize karma as action, and see the significance of every action. Speech allows us to do this. Observe your speech, and how you construct dis-satisfaction with it. Observe kind words and how they construct open-ness. Keep practicing... Slowly, your speech will dye the whole bucket.