Human activities have their place in a teleonomic hierarchy in which automatic processes serve functions in higher-level actions which, in their turn, are consciously controlled. This contrast between control and absence of control is also basic to the human conception of situations as it is mirrored in the grammatical structure of languages. In linguistic activity, the teleonomic hierarchy manifests itself in the differential processing of units of different levels: at discourse level, operations and units are chosen and combined freely, while at the morphological and phonological levels, selection and combination of units are determined by the language system.

Automation of an action assigns it a low level in a teleonomic hierarchy. Grammaticalization of a linguistic operation or item moves it down to a lower level of structure, where conditions for the use of items are more uniform. The mechanical conditioning of the use of a grammaticalized item distinguishes grammaticalization from other expansive changes. It leads to automation. Automation, in turn, is essentially unidirectional. The automation of grammaticalized material therefore explains the sporadic nature of degrammaticalization.