One cannot really explore solitude without also entering into silence. As far the spiritual disciplines goes, I have always considered silence and solitude as part of the same practice, like two hands washing each other. As such, if I am to recover from my SDD - my solitude deficit disorder - I will also have to reclaim my right to silence.
So then, silence.
Maybe the best way to emphasize the need for silence in our lives is to consider the alternative, a life which Merton identifies as 'an uninterrupted flow of words which is finally silenced by death.' Elsewhere, he says the following: 'If our life is poured out in useless words, we will never hear anything, will never become anything, and in the end, because we have said everything before we had anything to say we shall be left speechless at the moment of our great decision.’