Lua 5.1.4 is the current programming language used on ROBLOX. Lua uses lines of code to tell the game what to do at a certain time or place. Robloxians call this scripting. Using Lua can be hard or easy depending on your scripting skills. Lua was designed by Roberto Lerusalimschy, Waldemar Celes and Luiz Henrique de Figueiredo. The latest stable version of Lua is Lua 5.2.3, but ROBLOX uses Lua 5.1.4. There are many places to learn Lua, like Roblox Wiki, this Wikia, or look up the many guides in the Roblox Catalog. A popular example of lua is this code to make a message:
local message = Instance.new('Message', game.Workspace) -- Insert a new message in the Workspace. message.Text = "Hello World!" -- Set the text of the message to "Hello World!". wait(10) message:Destroy() -- Remove the message after 10 seconds.
In 2006-2008, there were not many Lua scripts around. When Roblox hit 2009, it became very popular amongst players.
If you wanted to make a really neat game, you can use Lua to make something like Apocalypse Rising, or Catalog Heaven.
Knowing Lua is a requirement for anyone who wants to get a job at Roblox HQ as an Engineer.