All participants in a conversation must remain in contact with the stone during a conversation. This is usually accomplished by sitting across from one another and touching one's fingertips to the stone. Vessuna will sometimes use their tails instead, as they tend to talk with their hands.
Arcane apprentices get sick of churning out touchstones, but it is a large part of their "training." It does, it must be said, ingrain some ritual habits that later allow their attention to be focused on more important things in the course of working more complex spells. Polished stones are preferred, but not required. Any old rock will do. As a related aside, some communities far from urban centers will have a large "meeting stone" at the boundary of the village rather than individual touchstones. There they invite outsiders to come and talk to an elder or leader, often with both hands pressed flat against the stone between them as a show of peaceful intent.
- Access & Availability
- Touchstones can be had on the cheap on every street corner in every civilized place. In an odd twist, it's rather harder to make a convincing knock-off than it is to just create a touchstone, so there's little market for fakes. (However, there are those who create false touchstones as a practical joke item. Rather than delivering actual translations, these stones are programmed with a store of set phrases on a theme such as insults, parental nagging, or nonsensical platitudes.)
- The dumbest troll can use a touchstone. But just try convincing one to.
- The wizard Noeline stumbled upon the idea one afternoon over their tea. "If," they pondered, "we can use a rather simple spell to comprehend unfamiliar languages, then why would we not just create a magic item that would let people do this all the time?" Like most breakthroughs, it looked stupidly obvious in retrospect. Why hadn't arcanists been doing this since the inception of magic that crossed language barriers? We will, of course, never know.