It seems that Latin grammarians have been the first to consider the interjection as an independent part of speech. In Greek grammarians' taxonomies, the elements to be labelled later on as interjections, were divided into alogoi (elements outside the rational, articulated language, outside the logos) and elements subsumed to the class of the particles (epirrhemata, that is accessory to the main enounce). Given the latter classification, interjections will be viewed as an adverbial subclass, having the function of determining the verb, even when this was unexpressed, thus only implied (Dyonisus Trax, Techne; Appollonios, De adverbio) [4].

            Latin grammarians inherited largely the grammatical system elaborated by the Greeks. The original contribution of the former is rather absent (an exception could be Varro); the task of the Latin tradition was rather to reinforce, stabilize and disseminate the taxonomies and classes inherited from Greeks. The main innovation of Latin grammarians was actually the substitution of the class of article (absent in Latin, but developed later by Romance languages derived from it) with this new word class, the interjection. The golden number of the parts of speech remained thus unchanged, but with a different composition.

            According to indirect sources (records of Latin grammarians) the first author to introduce the interjection as an independent part of speech was the legendary teacher of Quintilianus, Remmius Palaemon (Ist century, B.C.). His work, Ars Grammatica (attested also by one of Juvenalis' Saturae, VII: 215) was a reflection of the grammatical system used at that time, meant to be, for centuries afterwards, the model for the Occidental grammatical tradition. The treatise included also rules for a correct pronunciation, and discussions of several specific matters such as barbarisms and the solecism, all accompanied by illustrative examples with quotations from famous writers. Remmius Palaemon's grammar was lost, and its content arrived to us only through indirect channels. According to later grammarians such as Charisius or Priscian, Palaemon defined the interjection on semantic and functional bases as an element without a stabile meaning, expressing emotions. Very interesting is the formulation "having nothing that can be taught", suggesting the lake of conceptual value, but also the difficulty in approaching the interjection with the same tools as those used for the definition and description of the other word classes:

            In the same place, Charisius (IV B.C.) presents, comparatively, the definitions proposed by Comminianus:

            And Iulius Romanus:

            The works of these authors are also lost, but the quotations extracted by Charisius allow us to recognize easily a general agreement as to the role of the interjection in language, due probably in part to the acritical transmission of definitions from one author to another, and thus to the lack of a real grammatical debate at that time. According to their definitions, the interjection are the expressions of emotions or affects that move and trouble the spirit, the logos; this is in accordance with a long tradition for which all manifestation of affectivity would contrast with the cognitive capacities of humans. The authors consider that it is possible to identify a specific interjection corresponding to each emotion, and the composition of such inventory does not differ widely from one author to another, as it could be seen below (2.4.2.).

            Diomedes, in his treatise dedicated to Athanasius, mentions the different treatment applied by Greek grammarians to those elements meant to constitute a new grammatical class:

            For Diomedes, the distributional criterion is not a sufficient argument to include the interjections in the same class with the adverbs, because interjections have a different and more complex syntactic regimen than the simple function of verbal determiner.

            Donatus, one of the most popular grammarians of the European tradition (together with Priscian), whose treatises, despites their lack of originality, reflect very accurately the grammatical system and the tenets of the time, argues for the separation of the interjection as an independent class for syntactic reasons: the interjection does not follow, and thus does not determine, the verb. He points out the possibility of interjectional conversions, from a wide variety of basis, not only adverbial:

            The Latin grammarian Priscian, in the XVth book of his Institutiones Grammaticae, called De adverbio et interiectione, insists on the necessity of dividing the Greek class of adverbs and introduce the new class of interjections, as proposed by Latin grammars: interjections are not simple accessories for an implied verb, at contrary they have, by their own, the meaning of a verb. Such a statement suggests, in nuce, that in this age the idea was already present of treating the interjection as the equivalent of an independent enounce. Prisician argues for a full semantics of interjections. As such, they are defined as words manifesting emotions, feelings, which are expressed when interjections are interposed in a referential enounce as exclamations. The author suggests also the possibility for interjectional conversion, based on the specific modality of signifying: each linguistic unit could be actualized interjectionally, if the enunciation is performed under an emotional impulse and with an exclamatory intonation:

            This main taxonomic difference between the Greek and Latin grammarians was the object of discussions perpetuated through the entire time of antiquity, up to the middle ages. The controversial issue of the separation of the interjections as an independent word class is attested in Latin grammars and treatises until late, in the XIIth – XIIIth centuries, and becomes a leitmotif of early European grammatical tradition. An anonymous commentary on Donatus' grammar, dated from the XIIth – XIIIth centuries (Commentum einsidlense in artem Donati) underlines the necessity of the separation of interjections from adverbs, even though a relationship can be identified between the two word classes. The comments points out the fact that interjection can have an adverbial provenience, but not exclusively, and examples from other languages than Latin and Greek (from Hebrew, for instance) prove the independence of the interjections which have their own specific functions and semantics. The observation of the anonymous author regarding the specificity of the interjectional inventory for each language justifies their treatment as conventional, rather than fully motivated signs, as some of the early modern linguists proposed:

            The overview of these fragments related to interjection, extracted from the Latin grammars present in Keil's collection suggests an interesting conclusion regarding the semiotic status of the interjections. In the framework of the wider controversy on the origins of language (end of the XIXth and the beginning of the XXth century), interjections were viewed as motivated signs by excellence. In support of a view opposed to this, it is interesting to note that the inventory of the linguistic units labelled as interjections, exemplified by quotations from the Latin literature, is quite different from the repertory of the descendant Romance languages. It would be an argument against the theory that interjections are worldwide the same, because they are motivated signs, that do not belong to language. The few of them inherited by Romance languages from Latin may turn out to indicate phonetic or semantic evolution, a behavior less expected for a motivated sign, that diachronically keeps its motivated status. There are also cases of borrowings from other languages, attesting a phonetic evolution, exemplified for instance by the conformation of Greek loans (having the function of interjection in both the source and target languages) to the phonological system of the Latin, or even an evolution of the syntactic regimen. All such arguments plead for the conventional nature of interjections as linguistic signs.