I would consider GML to be an API more than a language, similar to SDL, but while not as powerful with the options given, GML covers a wider selection of options. For instance, SDL is more low level, while GML covers things SDL doesn't, such as, (but not limited to), physics and dialogs. SDL is written in C, but GameMaker is written in C++, Java, and Objective C++ depending on the platform. GameMaker's language syntax is very loose compared to C and C++, and should be a more fair comparison to Javascript in that regard.