types of inscriptions

To write is to inscribe on a media like paper.
To speak is to inscribe on a media like air.
A writer inscribes. A speaker inscribes. This is Derrida's logic.


But Deleuze writes that the activity of thought takes place primarily in writing, and not in dialogue and discussion. And Einstein says that his pencil is smarter than himself.


I am not sure why one type of inscription is different from the other.
We inscribe on a media like the world.


Do we actually inscribe? (I better go and write something longer about this)