Atthi: Exist.
Natthi [na + atthi]: Non-exist, no, not, not present.
Attā: Self, soul (Sanskrit: Ātman)
Hence, the SN 44.10’s two questions by the wanderer Vacchagotta (Pāli):
Q1) “Atthattā?” [Atthi + attā]: Exist + self?
Q2) “Natthattā?” [Natthi + attā]: Non-exist + self?
Chinese Āgama parallel at SA-2 195 agrees with the Pāli:
Q1) “一切眾生為有我不?”: “All beings have self?”
Q2) “為無我耶?”: “Not have self?”
Later, in the sutta, Buddha explains, he didn’t say “yes” to Q1, because it would be inconsistent with his claim of arising of the knowledge that “all phenomena are non-self (sabbe dhammā anattā).”
And, if the Buddha said “yes” to Q2, the wanderer Vacchagotta, already confused, would have fallen into even greater confusion, thinking: “It seems that the self I formerly had does not exist now (ahuvā me nūna pubbe attā).”
It appears the Buddha thought the idea of the non-existence of a self is incomprehensible for the wanderer Vacchagotta.
It's clear that by the time of the Three Qin (三秦) period (352–431 CE) when the sutta was translated, the Chinese translator/s also understood the attā as self (我).
