Seems to be ECMAScript or similar
Maybe it looks similar, I'm not familiar with ECMAScript, but here a quote from wiki:
Game Maker Language (GML) is the primary scripting language that is interpreted similarly to Java's Just-In-Time compilation used in GameMaker, which is usually significantly slower than compiled languages such as C++ or Delphi.
The syntax of GML borrows aspects from other languages such as C, C++ and JavaScript, giving it some syntax features of object-oriented programming but is not fully featured in that custom structs and classes are not possible. GML is an unusual language in that it only has two types, binary-safe (prior to Game Maker 8.1) strings and double-precision floating-point ("real") values, with complex data structures having to be referenced using integral float-point handles.
Version 1.2 introduced LLVM or, in GameMaker's context, the GameMaker Language Compiler (GMLC). The GMLC first turns GML code into C++ code, which is then compiled via Clang. This boosts the performance for logic-heavy games but does little for graphic-heavy games.
Anyway, I guess for those who want to switch to another engine (from Acknex) and don't really want to go deeper into C# and Java, it seems to be the easiest option. Plus there is multiplatforming etc.
