On a visit to a publishing house in Hove, England, I was greeted by the publisher with the unlikely sentence 'Ribena is trickling down the chandeliers.' (Ribena is the brand name of a flavored drink in the United Kingdom, and it was indeed dripping off the light fixtures.) Here, the sentence is first broken down into an NP ('Ribena') and a VP ('is trickling down the chandeliers'). There are noun phrases (NP), verb phrases (VP) and prepositional phrases (PP). For example, we can break sentences down into phrases, and then apply recursive rules to tack phrases onto phrases, or embed phrases within phrases.

Recursion can be much more complex than simple repetition, and it is used in human language to provide qualification or to add complexity to an utterance. Milne's Winnie the Pooh: 'It rained and it rained and it rained.' This example, though, is rather trivial, since it simply amounts to repetition, presumably to create a sense that it rained for rather a long time, causing Piglet some ennui. This particular rule, invoked twice, creates the following sentence, found in A. Rewrite rules of this form are a conventional way to show how language is constructed. Where the arrow is a symbol for can be rewritten as, and S stands for sentence. Perhaps the simplest example is a sentence that is composed of sentences, according to a rule that might be expressed as

Grammatical rules in language exploit recursion to create the infinite variety of potential sentences that we can utter and understand.

You dont know js recursion