Star Player of the Zanarkand Abes

[Stecloud]

Because technically, in FFX, Tidus never mentions his name once, and nobody asks him for his name.

Therefore, NOBODY ACTUALLY KNOWS HIS NAME :O

Auron does.

Not to mention that people say it during non-voice-acted scenes, so I assume it's a pronunciation problem.

Auron never does. It's not said because you can rename him so in order for his name to be spoken Square would have to have all the voice actors record various iterations of every name and combination of letters under the sun - it'd be too much work. Why they let you name him though, I don't know, because some scenes would flow a lot more easily if you couldn't and they simply kept him as 'Tidus'.