Distinguishing onomatopoeias from interjections

•We define interjections.•We define onomatopoeias.•We list every crucial difference between interjections and onomatopoeias.

Interjection is considered in many grammars and dictionaries a part of speech into which a great diversity of words are ranked, including fillers, primary and secondary interjections, exclamations of all kinds and onomatopoeias. The aim of this article is to distinguish onomatopoeias from interjections on a semantic and grammatical standpoint. Indeed, the definitions of interjections that are given in the specialized literature do not match at all with the concept of onomatopoeia. For this purpose, different points of view, belonging to several linguistic schools like Dependency Grammar, Cognitive Linguistics, Theory of Enunciative Operations, Relevance Theory, will be displayed in order to launch a dialog between those metalinguistic discourses, offer an overview of the analyses of interjections and explain why onomatopoeias are not interjections. Whether or not interjection can be considered a part of speech will also be discussed: even though part of speech is a prevailing concept in linguistics, its definition is as vague as essential.