Originally Posted by Gem
In the sense that dhamma can be talked about, it is expressed in words. Where words are concerned there is a principle of 'right speech', and 'right' doesn't mean what is written in text is the truth so much as it pertains to the intent behind what is said.
This can lead to regulation and obedience to prescribed acceptable language, and it often does, which has a place in silent meditation retreats to ensure there is no 'wrong speech' (eg such as deception). But in regular social life that doesn't apply.
In the context of this internet thread, speech is necessary, so the dhamma would involve being conscious of what you say, and what motivates you to say it. The basic lessons of truthfulness, kindness and compassion are promoted by all religions and spiritual ideology under the pretext of 'good-will', which generated by a loving heart without malice, is an undying wish for the greater happiness of all living beings ('metta' in Buddhist lexicon).
So, you see, the dhamma in regard to what can be said might refer to the established Buddhist texts and what can be said about them, but moreso, dhamma is 'the way' things are said, consciously, with emphasis on the 'good-will' behind what is spoken.
As you correctly pointed out, "in the context of this internet thread, speech is necessary". However, although it is not possible here, communication without speech is far more effective.
When I was at a Taoist monastery in Chengdu (China) many years ago, I had questions for the monks (through an interpreter) that were not answered to my satisfaction. There was a similar problem with the head monk. I was then referred to the master and admitted to his presence albeit without my interpreter. It is not clear whether the master spoke English or not but it did not matter. I was in his presence for about three hours with no words being spoken yet all my "questions" were answered to my satisfaction until I had nothing more on my mind.
A similar silent communication just happened between me and a great soul at the Khumba Mela in Haridwar (India) in 1998. The silent communication was far more effective than anything that I have either read or have heard where words were utilized.
Having said that, the Buddhist texts have been very helpful .... until one no longer needs them. Over time, I have noticed that the self-realized great souls are, more often than not, more quiet and speak less than others. Nisargadatta Maharaj points out that there are numerous primary teachers to teach the alphabet.