Telecollaboration projects enhancing intercultural communicative competence and second language acquisition in the long term have increasingly interested a lot of authors and researchers, especially concerning university students all around the world. In this paper, however, we intend to go beyond on this field and embrace Secondary Education pupils on its research, analysing and comparing their production in two environments: chat and videoconference tools (BigBlueButton, particularly). Discourse analysis of chat and BBB sessions is explained in detail, following a set of criteria for each variable of interest. This data help us to set up specific patterns characterising communication in each environment and point out some interesting conclusions; while chat sessions generally show a-straight-to-the-point communication, in which misunderstandings, interaction turns for the same (sub)topic and lateral topics are less present than in BBB, in BBB there is a less rigid scheme, being easy to introduce lateral topics and intercultural aspects. Besides, in BBB there are normally more interaction turns for a (sub)topic, embracing repetitions, reformulations and negotiation of meaning. Furthermore, there is more emphasis on misunderstandings; native speakers show willingness to help the non-native ones, these last showing a lot of interest, a general high production in terms of interaction turns and making efforts for being understood. Nevertheless, silences, overlaps and misunderstandings arising from technical problems with sound are also present in BBB. Accordingly, in chats, less silences and time lost on technical difficulties with sound are remarkable, as well as the politeness in starting conversations and changing into another language