So this has been bugging me for a while.
How do we determine how a Japanese name is meant to be written in Roman letters? Especially in cases where the Japanese write it several different ways?
The one that inspired this is (quelle surprise) Jirarudan. Most people use that version, although now the Bulbapedia claims it's not the "actual name". Now I'll admit I don't know Japanese, but I know a lot of people who do, and they've said there's multiple ways of writing ジラルダン out that are all equally legit. Yes it's (more than likely) derived from "Girardian", but we don't know how exact the writers wanted it to be to the word.
Someone said "I guess we won't know unless the makers of Pokemon spell it out", but even that has problems (and also the character credit I have on my copy of his image song from the movie soundtrack is "Jiraldan", further complicating issues).
To branch out into other characters (I can see you all going "FINALLY!"), a well-known example if that is Meowth. I've seen official Japanese merchandise that spells his name Nyasu, Nyasuu, Nyarth, and Meowth. Yes, the English name. Are all of these then taken to be "official" spellings of ニャース?
And then we have the issue where the official spellings were clearly written by someone with no knowledge of the language the word is from (Prasle anyone?)
There was even the issue of Denji vs Denzi, even though denji is a Japanese word.
So with a translation/transliteration barrier, how can we be sure which words and spellings are the intent? If there's multiple possibilities, as in my first two examples, are they all technically correct?