Forth is described as 'Imperative stack-based computer programming language and environment' and is an app in the Development category. There are six alternatives to Forth for a variety of platforms, including Mac, Windows, Linux, BSD and Android. The best alternative is C (programming language), which is both free and Open Source. Other great apps like Forth are C++ (Free, Open Source), V (programming language) (Free, Open Source), Object Pascal (Free, Open Source) and Pike programming language (Free, Open Source).
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose, powerful programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features.
Pike is a dynamic programming language with a syntax similar to Java and C. It is simple to learn, does not require long compilation passes and has powerful built-in data types allowing simple and really fast data manipulation.