When Final Fantasy XII was introduced in Japan for the first time, Balthier's name was actually "Balflear". Consequently, his name has remained the same throughout the course of years before its Japan release. Several months later, during a press conference concerning the North American release for the game, his name was changed to "Balthier". Other names were changed accordingly, such as "Valentia" to "Valendia".

Balflear, his name in Japanese, is written in katakana. In Japanese, words written in katakana, as opposed to using kanji and/or hirigana, are used to most often to signify foreign words. "Balflear" is written as: バルフレア (romaji: Barufurea)

Balthier's real name is Ffamran Mid Bunansa. The only two people who you will hear him be called by that name are Jules and Doctor Cid. Ffamran Mid Bunansa is also written in katakana as ファムラン・ミド・ブナンザ (romaji: Famuran Mido Bunanza)

Bunansa, his last name, is a tranliteration error. In katakana, his late name is written as ブナンザ, with the last syllable pronounced as a za (ザ). This error was most likely intended; perhaps it was for the sake of sounding better, or maybe to distinguish from another Final Fantasy character, Mustadio Bunanza from Final Fantasy Tactics (more details here).

His middle name, "Mid" is shared with the first name of a character from Final Fantasy V, Mid Previa. He is the grandson of Cid Previa, and has a specialty in mechanics. The origins of his name are unknown, and it doesn't seem like he was named after anyone. Middle names of Archadians are a special case, unlike Ashe or Rasler, whose middle names of B'nargin and Heois respectively, are hailed from the first names of the 2nd son of King Raithwall, House of Dalmasca, and the 3rd son of King Raithwall, House of Nabradia. Archadian royalty (Vayne Carudas Solidor, Larsa Ferrinas Solidor, Gramis Gana Solidor) do not have this tradition because they were not originally empires formed under Raithwall.