==== Syntax of Languages ====

Text-based messages and languages have higher-level syntactic properties. These syntactic rules are known as **grammatical rules**. The grammar of natural languages has evolved historically, and the grammatical correctness of a given text is not always clear-cut. In contrast, the syntax of artificial languages is much more precise. Among the languages constructed to replace natural languages, the most famous and significant is **Esperanto**, created by Zamenhof. Languages built for scientific and technical purposes are subject to strict requirements. From an information science perspective, **mathematical axiom systems** can be considered languages.

The languages created by **computer science** and **information technology** describe computer programs, control programs, protocols, data, facts, and knowledge bases.

  * **Processor instruction sets**

  * **Programming languages**:
    * **Assembly languages**
    * **Sequential languages**:
      * ENGLISH, FORTRAN, COBOL, PL 1
      * BASIC, Visual Basic
      * PASCAL, Delphi
      * C, C++, Visual C++
      * ADA
      * Java, J++, Perl, PhP
    * **Logical languages**:
      * LISP, PROLOG
  * **Command languages**: BASH
  * **Configuration languages**: YAML
  * **Object description languages**: HTML, XML, EDI
  * **Simulation languages**: SIMAN, TLI
  * **Technical programming languages**
    * **CNC programming languages**:
      * ISO NCL, APT, EXAPT CLD
    * **Robot programming languages**:
      * VAL, AML

Using **languages**, complex expressions can be created by applying terminal symbols, keywords, and rules. A **program** is an ordered set of such expressions. A program is a finite sequence of expressions written in a programming language, representing a computer-interpretable and executable realization of an algorithm.