The essence of any programming language is its "parse tree".

Natural languages can be conceptualized and described as forests of cognitive structures.

https://commons.wikimedia.org/wiki/File:Genealogical_tree_of_programming_languages.svg

more on languages, evolution, etc. in my Prolegomena Paedagogica wizzion.com/PP.pdf

https://sanskrit.inria.fr/

In formal language theory, a grammar (when the context is not given, often called a formal grammar for clarity) describes how to form strings from a language's alphabet that are valid according to the language's syntax. A grammar does not describe the meaning of the strings or what can be done with them in whatever context—only their form. A formal grammar is defined as a set of production rules for strings in a formal language.

A formal grammar is a set of rules for rewriting strings, along with a "start symbol" from which rewriting starts. Therefore, a grammar is usually thought of as a language generator. However, it can also sometimes be used as the basis for a "recognizer"...

https://en.wikipedia.org/wiki/Abstract_syntax_tree

while b ≠ 0
  if a > b
    a := a − b
  else
    b := b − a
return a

"Strictly formalist, transformationalist approach had failed to furnish a complete, consistent elegant framework for the study of natural languages but