I think a simple answer would be that any speech that comes from a kind heart (in the unemotional sense) would help make it more like Buddha speech.
If someone is a little bit emotionally disturbed and shaken, then the speech expressed may reflect these internal disturbances, and this may in turn be confused for a kind heart. A kind heart flows not from emotion, but from a clear conscience. When the conscience is clear, the heart is kind and beneficial speech and activities follow. When the conscience is clear, the speech becomes more like Buddha speech.
I believe that the reason why we call it Buddha speech is because there is simply no agenda at all. We can see this from the very sutras that we have; the very teachings and actual words of Buddha reflect this. It is pure generosity, it is genuine sharing – the ultimate form of sharing.
There is a saying that sharing is loving. In this case, the Buddha’s teachings are the perfect example of this. Buddha’s genuine sharing is a reflection of limitless love.
So what are the qualities of Buddha speech? Having perfected not only speech, but action and thought over many eons (basically meaning over many, many lifetimes); where there is simply no need for any agenda, as one can see the faults within any kind of agenda; seeing the positive qualities of generosity and kind heart; and then simply sharing knowledge.
Let me give an example. I think most of you are familiar with the various aspiration prayers. One that comes to my mind is that of the Samantabhadra Aspiration Prayer. It is perfect in every way. There is simply not one sentence – in fact, not one word or even one syllable – that is not a Buddha speech. (Unless, of course, it has been wrongly interpreted or written in some way).
Of course, all of the sutras and the teachings of Buddha are examples of Buddha speech. They are perfect because there is no self-interest, agenda, or expectation of something in return. It is pure giving. It is genuine sharing.
Going back to the characteristics of Buddha speech, an important question to ask is if something is beneficial. Speaking about the weather, for example, may not be particularly useful (except in certain circumstances). If speech is beneficial, if it is useful, then it is worth considering. Otherwise, it may be better to leave it. Understanding the context is important, as some things may be beneficial in some cases but useless in others, and vice versa. It is also important to consider how much control we have over our speech, thoughts and actions – how much composure do we have as an individual?
There are times when one can engage in various speeches, engage in various topics. Whether it is talking about the weather, painting, cooking, baking, sports – whatever – it doesn’t matter so much, as long as it is beneficial.
But what does it mean for speech to be beneficial? From a Buddhist point of view, when we use the term ‘beneficial’, it often refers to two things: beneficial in this life and the next life. Beneficial speech will help us reach liberation and then gain Samyakasambuddaya.
So if it helps an individual and others, we can engage in seemingly pointless speech. We can whistle, hum, whatever – as long as it is beneficial. Maybe, for some people they like to hum – maybe humming is their hobby! Maybe it is their passion, maybe it is the thing that really makes their day. If they are not able to hum that day, for them it is a bad day. They may not be able to sleep properly, they might have nightmares. For someone like this, it might be helpful to encourage them by humming along with them, to help them reach liberation and enlightenment! You hum a little and you get closer, when you hum twice even closer, and a little more to a point where one can maybe have a conversation! Yes, understanding the context and what is truly beneficial is very important.