Language

Throughout the Final Fantasy series, there are a number of scripts and writing systems. Typically, they are merely substitution ciphers, with one symbol corresponding to each character in the Latin alphabet, but this is not always the case.

Cetran Writing
The Cetra seem to have their own unique writing system. Nothing is really known about it, but it appears to have a basis that is primarily pictographical rather than alphabetical.

Terran Writing
The language of Terra, with its own unique script, appears in the game particularly in locations such as Oeilvert that are of Terran origin. Of the party members, only Zidane is capable of deciphering it.

Spiran Writing
The Spiran script is seen throughout the game, especially on Blitzball-related media. In particular, the logos of the Blitzball teams contain stylised versions of the script, while the word "Blitzball" is inscribed on the ball.

Al Bhed
The Al Bhed seem to have their own script, as well as the language itself being a cipher.

Unknown Script
The bills posted for Hunt Marks are written in an unknown script.

Cocoon and Pulse Writing
The scripts used by the civilisations of both Cocoon and Gran Pulse are essentally just stylised versions of their Latin counterparts. Most of the letters and numerals can be deciphered quite easily.

Unknown Writing
Inscribed on the Eidolons is an unknown script. Like the other two scripts, it is reasonably easy to decipher some of it. Its origin is unknown, although since it appears on the Eidolons, it could be speculated that it is somehow linked to the Goddess Etro.