> What exactly is 'inchind dermait'? All this time I assumed that Cend
> Fáelad had been suffering from amnesia when a blow to his head cured
> him. The last passage implies that 'inchind dermait' is the normal
> forgetfulness of every person and the blow to Cend Fáelad's head
> removed his ability to forget, leaving him with something like a
> perfect memory.
Yes, that's it.
> That leads me to another question. Was he taken to Túaim nDrecan by
> chance to convalesce, or was he taken there because his people
> realized that something unusual had happened to him and they wanted
> him to be studied by experts in all branches of learning?
Since all we know about the story is the short episode we are reading at the moment, this is impossible to answer. My personal impression is that he was simply there for
reconvalescence, and that it was by sheer chance that he picked up all the knowledge that was taught around him.