According to Capcom USA's Product Manager Scott Smith, the reason why Gouki's name was changed to Akuma for the international release of Super Street Fighter II Turbo is because he felt there were too many characters whose name had the letter G. Smith chose the name 'Akuma' based on a news story from Japan where people were trying to name their child after the devil, but the government wouldn't let them. Smith looked up devil in Japanese and found the name Akuma.
Contributed by ZpaceJ0ck0