There are no peculiarities or quirks to the Chinese rendering of anattā, it is a rather straightforward coinage, interpreting the a- as “without/not/lacking” (one word can cover all of these functions) they used 無 (wú), and for attā, they elected to use a pronoun, namely “I/me” 我 (wǒ). “Without me”, “not me”, these are some very straightforward ways to render this, IMO at least.
However the matter is not so straightforward when the Chinese Dhamma has to talk about attā by itself. One would think that 我 could serve as a rendering for attā alone, however this would probably cause a lot of problems of intellegibility in the Chinese, having this pronoun function frequently as something other than a pronoun. There is the possibility of 自 (zì), which often means “one’s self”, but it has the drawback of ideally requiring a verb immediately after it to be intelligibly read as a reflexive.
What they elected for was, among other adaptions likely, 是我 (shì wǒ) & 有我 (yǒu wǒ), two “special” clarifications of 我. The meaning and ramifications of these clarifications are what interests me here in inquiring, and how that impacts selflessness in EBTs.
The 是 in 是我 often means “to be”, “exists”, “really”, and “correctly”. Somewhere among those readings may lie why this adaption was chosen, as it is close to the second adaption: 有我
有 is listed in the NTI dictionary as being a frequent stand-in for bhava in translated Buddhist Chinese. It would be interesting if this pointing to something like a “bhava-attā” form in the Indic originals, but I know nothing about Indic languages and if such a thing can ever be demonstrated to have ever possibly existed as a word.
Any thoughts as to why these specific characters may have been chosen and why 無我 appears to feature no qualifiers before 我 and its opposite does? Is there a similar phenomenon in any other languages of EBTs? This could be very interesting, because it would say much about how the early translators themselves understood the Dhamma.