The notion of non-verbal communication refers to all signs and non-linguistic sign systems employed to communicate. Within such a broad definition, two types of constitutive elements can be distinguished. On the one hand, one category encompasses sings and cultural systems of sings; that is, the habits and beliefs shared by a community of speakers. On the other, there are non-verbal systems of communication within which the author lists the following: vocalics or paralanguage, kinesics (i.e. body movements), proxemics or the use of space and chronemics (i.e. the study of the structure of time). After a brief theoretical introduction, the paper concentrates on the latter type of systems, and more particularly, on paralanguage and kinesics, two subcategories within non-verbal communication which are argued to be clearly involved in discourse phenomena like irony. This issue is only programmatically discussed at the end of the present article.