A natural language is a “normal” language spoken by an human being.

In Data-processing, the natural languages are opposed to:

• machine languages: directly interpretable by the Processor of a Computer, but not very readable with the eyes of the programmer
• computer programming languages: comprehensible by the programmer and easily traductibles (compilable) in Machine language
• formal languages: defined starting from an alphabet and of a certain number of formal rules

The challenge that the editors wish to raise of search engines is to be able to give relevant results to a request formulated in natural language.

Alan Turing, mathematician American of first half of the 20th century, in addition conjectured that an artificial intelligence could give the impression of " so much well; parler" that it would be difficult to distinguish of a being humain.
Voir the Test of Turing.

See too

• http://www.cnlp.org/