A linguistic model is a system of data (features, types, structures, levels, etc.) and rules, which, taken together, can exhibit a “behavior” similar to that of the human brain in understanding and producing speech and texts. A functional linguistic model takes into account the observed language behavior of human beings rather than the physiological activity of the brain. This behavior is reflected in the texts or speech they produce in response to the texts or speech they perceive.
So far, the direct modeling of the brain structures has failed, and several functional models were proposed for the sake of computational linguistics. The modern functional models have many features in common. They are intended to be quite formal, have a dynamic and non-generative character, provide independence of linguistic algorithms from linguistic data, and consider dictionaries as one of the main, inalienable parts of the model.
Theoretical approaches provide a solid basis for both holistic and reduced models of language oriented to applications. The degree of the reduction in such a model heavily depends on the specific application.