This article is about programming languages in general. For the project type, see Programming Language (Project Type).
A programming language is a set of rules and functions that let us use a computer. Programming languages are designed to make it easy for humans to write complex instructions. They function a lot like human languages: they have explicit grammars and a primitive vocabulary. Scratch is a programming language.
Syntax and grammar
Programming languages relevant to Scratch
Squeak was used to program the 1.x series of Scratch. It is a simple language designed to be human-readable and concise. See Squeak Tutorial for a simple introduction.
Adobe's Flash was used to program Scratch 2.0. It is programmed in ActionScript, which was based on ECMAScript.
Python is a simple interpreted scripting language that is used in the Scratch 2.0 back-end (server-side code). The forums run on DjangoBB, a Python library. Python is also used in many Scratch add-ons, including Kurt.
PHP is another server-side language which was used to build the Scratch 1.x server system (ScratchR).