It is not pronounced Teedus in Japanese, but Teeda (Te-i-da), still "Tidus" (with "Teedus" as pronounciation, can also be seen in the Japanese Dissdia for example) is supposed to be the actual translated version of his name, just like "Za-kku-su" is not supposed to be "Zaks" but "Zack" (can be seen in the Japanese Crisis Core for example). It kind of depends. Golbez would be Golbeza, Firion would be Frioniel, et cetera.