A short look at the grammatical tradition or at the modern studies on language, confirms the fact that interjection is indeed a most "neglected part of speech". It is not the place to go deeper into the controversy regarding the linguistic character of interjection and its integration into the grammatical system of a given language, as a "part of speech", with all its terminological and theoretical inadequacies. However, the heterogeneous elements traditionally included in the class of interjections have only seldom awaken the interest of language scholars, and are generally considered as peripheral phenomena, or even excluded from the language, therefore not able to constitute an object of linguistic studies. In grammars from all centuries, interjections are "disposed of" in a few words, in chapters at the end of these; in comparison with the tents of thousands of titles, volumes and articles, considering every other word classes, those dedicated exclusively to interjections are less then a few hundreds.

            The low interest on interjection is probably due also to the fact that the traditional study of language has favoured mainly the written language, imposed since the classical antiquity as the normative and stable model, in opposition with the spoken language, the field of manifestation for "errors", "deviations from the norm", or "accidents". The interjection is essentially a phenomenon belonging to the spoken language, only sporadically present in its written form, in those types of discourses attempting to reproduce orality.

            Only for the last decades, it has been possible to talk of a noticeable interest in the spoken language, favoured also by the technological and theoretical progress able to allow the collection, stocking, manipulation and exploitation of spoken language resources. We owe to the new "corpus linguistics" orientation, which, by its methods, techniques and results has led to a change of the epistemological paradigm in the present linguistic research, an opportunity to appropriately study and understand the functioning of interjections in verbal communication and their specific way of signifying.

            Despite the new interest for spoken language and everyday verbal interactions, the elements labelled as interjections remain an unexplored field of research. The various grammars, elaborated from a normative or merely descriptive perspective, perpetuate, usually only with slight variations, the definition and the descriptive structure imposed by the classical tradition. They give a ‘'semantic" explanation of each interjection, illustrated by a series of eclectic examples, sometimes accompanied by an attempt to classify the interjections on the basis of the semantic and semiotic criterion of the referent, that is the ‘'feeling'' or the ‘'emotion'' expressed by the interjection. Such classes often include very heterogeneous elements, from simple aspirated vowels to larger syntagms and phrases, made up of two or three units, without a valid justification of their common categorization. For some authors, the mere exclamatory intonation, ascendant-descendant, and a specific stronger intensity of articulation would be sufficient to lead to an interjectional conversion [3] of every other linguistic unit.

            There are numerous unanswered questions on the interjection, proving the controversial nature of this "category". Do the so-called primary interjections belong to language? Are interjections arbitrary or motivated signs, or both? What kind of relationship is there between primary and secondary interjection? Is there any possibility for formalization or a general theory of interjection? Why are they so numerous in the spoken language, and almost absent in its written version? Why do linguistic studies avoid approaching them? And many other questions, debates, and controversies, whose origins may be traced back to the works of the Latin grammarian in antiquity.