Do note that Adi and Addie are pronounced differently (as they are, after all, entirely different names with different etymological backgrounds) except when Adi is being offered as a typographical variant of Addie. The
harder sounding Addie is much more familiar to English users, as it is the English/Germanic option of the two and is the predominant variation in western countries.
The
softer sounding Adi is perhaps primarily recognized as a Jewish name by Westerners, though a similarly spelled (and from what I can google, similarly pronounced) name (or nickname) exists in Indian, Middle-Eastern, and Latin languages (and possibly others I am unaware of; I did see some other associations within previous comments), though each of the various "Adi" names do have differing name meanings and etymological backgrounds.
Which leads us to a point in favor of Adi- due to so many backgrounds forming a nearly identical name, it is much more widespread in its familarity than Addie (especially as a male name, given the typical gender associations of the two spellings).
On the other hand, this is a translation into English, where Addie is much more recognizable [however, that only as a female name, see below(*) ], and not into a language where Adi would be more intuitive.
Were we just working off those elements, I'd say it's a fairly even shot, with Addie being slightly preferable. However, there's one additional factor to consider:
Adi and Addie are from different etymologies and exist as different names, but Adi can
also be a variant form of Addie.
Hence using "Adi" would allow readers to interpret the name as best suits them (while Addie would actually be forcing a restriction to a single one of the names).
Therefore, I'd consider Adi'd be the much more appropriate choice, assuming a situation where the original text is ambiguous in how it should be translated. (**)
(*) That said, that line of thought was made while ignoring typical gender associations. However, with those in mind, it should be noted that we're naming a male. Thereby, Adi'd be all the more the definitive choice, as Adi is also the more typical male form in English (as well as being male-oriented in several other non-English languages). Addie is far more typically associated as being a feminine form (at least under the consideration of a proper name, rather than a nickname).
Well, putting aside more determinative processing and moving over to subjective considerations, I have gotten rather used to thinking of the character as an Addie.
Rereading the early chapters and looking at his character, I do think it likely the author intended him to be an Adi but, at the same time, I don't really feel Addie is all that ill-fitting either.
In the end, the only wrong choice here would be for the translator to make their determination off public appeal [ie, polling which name is more popular]. Be it off logical determination, matching author's intentions, or fulfilling the grace a translator has of being able to best determine what translation would most appropriately convey meaning to the audience in question, any of those approaches would be easily defensible and well-suited to addressing the matter. Trying to poll out subjective opinion, however, would invariably circumvent the considerations a translator should be working off of, and end up being no better than a coin toss as far as suitably resolving the matter.
(**) However, as I mentioned earlier, such considerations are for when the translation is ambigious.
If both the author AND language expectations deem the name to be "Adi", then I'm not seeing why there's any argument towards making the name Addie.
We're only a few chapters in, us readers can still readjust to a translation tweak just fine.
--
@GodGinrai "If it had changed the pronunciation, I would have suggested you change it to be consistent. But since it is pronounced mostly the same, I would say it is fine to keep it as-is."
I dunno, maybe it's 'cause I'm used to actually hearing both name variations, but I feel the pronounciations (linked for reference in the text above) are rather different.
Kinda like, I dunno, Mickey and Michael (
Micah/Micha'd probably be a more fitting option for comparison to Mickey here, especially in that it is also Hebrew the same as Adi can be, but I don't imagine too many people are familiar with that name). Clearly similar, but also very distinct.