x1 is conscious, aware, capable of understanding experiences to some degree, and capable of forming new and lasting experiential memories, and has some sense of defined and stable self/identity/personality according to standard x2.
Parallel to "jmive". The experiential memories are se vedli. Humans usually begin to become zamveka after a few years, with it being patchy until pre-adolescence. They say that everyone remembers where they were when they found out that some major public event (such as JFK's assassination or the September 11th attacks) had happened; but, in reality, such claims apply only to people who are zamveka (and thus excludes very young children). The idea of this word is that it captures the notion of a human's (or other being's) 'effective life' rather than their technical one, at least from the standpoint of retrospective reflection by that person. A person who undergoes substantial neurological or psychological trauma or modification such that they have a new, separate personality afterward and have few if any memories from prior times may say that their own (new identity's) period of zamveka began after that trauma/modification event. Persistence of sense of self is implied to some degree but the set of times during which zamveka is achieved by a given self/being need not actually be continuous (although it will essentially be experientially so for them, perhaps modulo things such as sleep).