The basic programs responsible for running the game are called scripts.
Generally, commands like [Show Text] can also be called "scripts", but in RPGXP, scripts are even more than event commands and are closer to the concept of a computer program. Event commands are not actually handled by the program, but are in fact parsed at the script level.
Script editing is a difficult task, aimed at advanced users who wish to customize the game system itself. However, there is absolutely no need to learn anything about scripting if you only intend to create a game in the usual way. At first, just try your hand at game creation without worrying about scripts; when the default system isn't good enough for your needs, it's time to take a closer look at scripting.
About RubyRPGXP's script engine doesn't use a proprietary simplified language, but the
powerful scripting language Ruby. Ruby's official Website is
Ruby Programming Language.
Ruby is freeware developed chiefly by Yukihiro Matsumoto, and its capabilities are more than sufficient to script a large-scale game. However, since it was originally conceived to be specialized in text handling and the like,
it's a challenge to develop a game using Ruby alone.
That's why RPGXP uses RGSS (the Ruby Game Scripting System) to adapt Ruby for use in game development. See the RGSS Reference for details.
The language can be referred to as "Ruby" or "ruby", but not as "RUBY".