The rapid progress of linguistic science, particularly after the emergence of modern linguistics, has revealed the unscientific nature of the traditional method, a characteristic that was primarily responsible for its inability to teach the language effectively.

Therefore, the alignment of language teaching with the principles of theoretical linguistics was necessary, as it not only created the conditions for its liberation from the shackles of traditional perception but also connected it directly with a related and simultaneously dynamic scientific field that was not only capable of methodologically renewing it but could also provide it with the required scientific legitimacy.

However, the emerging possibility of linking the theoretical principles of linguistics with teaching practice gave rise to the idea of a broader exploitation of the findings of linguistic science in various fields. This fact led to the creation of applied linguistics, of which the teaching of language is now an autonomous scientific branch.

Taking the above into account, the present study is divided into two main parts: The first titled "Theoretical and Applied Linguistics - From Linguistic Theory to Teaching Practice" presents the developments in the field of linguistics and follows the history of the transformation of language teaching into an autonomous scientific branch, while the second titled "The Teaching of Language as Science and Technique" seeks to delineate the subject matter and to present its main characteristics, as they have been shaped after its organic connection with linguistic science.