Thanks for your questions. I think they are actually pretty common for non-hermits or for those whose notion of eremitical life is idealized. Similar questions could be asked about the other constitutive elements of the vocation including stricter separation from the world whenever "the world" is taken to mean anything outside the hermitage door. In each of these cases, solitude, the silence of solitude, and stricter separation from the world, what we find is that these terms are more nuanced than most people understand. None of them is absolute. By that I mean the eremitical life is not about absolute silence, absolute solitude, or absolute withdrawal from the world. Instead, these elements are real and substantial in a way that allows the vocation to be defined in terms of them, and at the same time, they are qualified by the needs of the hermit for growth, healing, and holiness as she moves toward maturity in her relationship with God and others in an ecclesial vocation.
So, for instance, no, I don't take a vow of silence nor do I hold myself to a Rule calling for absolute silence. I talk (to God and less frequently, to others), I sing, I listen to, compose (improvise), and play music, and all of this requires significant, but (obviously) not absolute silence. Silence is necessary to be a person of prayer because prayer is about listening and being available to God, and we are attentive and available to God so that God may recreate the world as he wills. That recreation begins with us and with the way God's love transforms us as human beings. Hermits cultivate silence for this purpose, not simply for itself alone. Moreover, silence can be external or internal; while both are important it is internal silence that is key in the hermit's life. The cultivation of inner silence and stillness is the aim of a life of stricter external silence. Whatever is happening externally leads us to the profound internal silence that allows for the song we are to rise up within us and be "sung."
What I am saying is that the hermit is silent and embraces silence to the extent it leads us to prayer and then, to union with God. The same is true of solitude. External solitude serves the hermit's life with God and her growth as a human being. One is alone with God for the sake of God's will and all that that Divine will desires and occasions. In some ways, there is also an inner solitude where the individual is at peace with themselves and with God. This solitude is about a harmonious relationship; one is truly oneself in this space, and one is oneself with God. It is the antithesis of isolation and when I write about it, I speak of it as the redemption of isolation.When c 603 speaks of the silence of solitude, most superficially it means the quiet that exists when one is not conversing with others or otherwise engaging with others, but at its deepest, it is an intimacy with God where God is allowed to be God and we are the human person God calls us to be. This silence of solitude is peaceful (though not painless!), profoundly energizing, and marked by a sense of solidity and love in and through which one is truly oneself. It is therefore also about being profoundly in relationship with the whole of God's creation and the whole of God's People. When I write about the silence of solitude I also speak of it as involving the quieting of our existential anguish and pain. We can be screams of anguish and then be transformed through the love of God into a quiet and joyful song of praise. And of course, sometimes the anguish recurs and our personal song is transfigured into lament. This is still vastly different from simply being a scream of anguish!
The bottom line in all of this is that when I speak of solitude it does mean being alone, but one is alone with God and, in varying degrees of intimacy, with all that is grounded in God. This is why I tend to usually say "eremitical solitude." There are a variety of forms of solitude; some are not healthy and most are not eremitical. The corollary is that when the hermit is not alone, but is with others, the inner silence and solitude of her relationship with God remains foundational. When a hermit has lived the silence of solitude for some time she does not need to be particularly concerned that contact with others, including occasional social functions, will destroy the silence of solitude that is so fundamental to who she is.