AbstractThe category of expressive speech acts has traditionally proven elusive of definition in contrast to other types of speech acts. This might explain why this group of speech acts has been less researched. The present paper aims to redress this imbalance by analysing the expressive speech acts performed by two groups of university students in two educational chats, carried out in English or in Spanish, respectively. The main purpose of the study is to find out if students express their emotions (and which emotions) when interacting online and, if the use of their mother tongue or not affects their performance of expressive speech acts in terms of frequency and type. To this purpose, Weigand’s (2010) taxonomy of speech acts was followed, since it provides a more systematic delimitation of the traditional category of “expressive acts”. Her distinction between emotives and declaratives was thus applied to the dataset under scrutiny. Results show that students opt for performing declarative acts but refrain from expressing their own emotions in an educational setting. As for the use of English or Spanish, no significant differences were observed, which reveals that the use of their mother tongue does not seem to affect the kind of acts performed.