Applied linguistics provides the bridge between the theoretical disciplines and
language teaching. It is also a problem-solving enterprise; its raison d'etre is
solving practical problems. It therefore performs an essential function in the
language teaching process. For example, linguistics provides language
descriptions of a particular language. The nel~d for this is sometimes obscured,
but becomes obvious as soon as we approach less commonly taught languages.
Two problems manifest themselves, however: on the one hand, language descriptions are often too technical and too t,heoretical for the language teacher;
on the other hand, the demands of syllabuses based on semantic and pragmatic
criteria have outstripped the available descriptive resources. Stem (1983, p.186)
points out that it is necessary to have an intermediate device, a pedagogical
grammar, which is an interpretation and selection for language teaching
purposes of the description of a language, based not only on linguistic but also on
educational and psychological criteria and used as a linguistic resource. This is
where the applied linguist performs a valuable function.