There are several languages within the game.

Language Skill

The language skills (lang/su'ndari for example) cover a characters ability to understand the language when it is spoken. It also covers his/her ability to understand a language when it is written as long as he/she also understands the script it is written in.

Literacy Skill

The literacy skills (lit/su'ndari for example) cover a characters ability to write and understand a specific script. It is helpful to think of a language such as Japanese for example as Japanese can be written in a tradition script or the western script. The character can write any language he/she understands (has a lang skill in) in any script he/she knows. For example a character could write the language old native in the su'ndari script but he/she can only read things written in old native script if he/she has lit/old_native even if he/she understands the old_native language.

Legal Skill

There are several documents that are produced via the legal skill instead of the above system. These documents represent certain legal processes that are done in a set and ritualised fashion. You should assume that they are written in lit/su'ndari and lang/su'ndari.