ENSchoolchildren’s language skills, especially those of expressing opinion and argumentation, can be developed in current primary school through mutual interaction, working in pairs or small teams. Every learner should first of all understand and then explain what (s)he has understood. This is the way to create knowledge (Bertin, Gravé, & Narcy-Combes, 2010; Narcy-Combes, 2014). Language learning also relies on thinking about the linguistic content and the grammar. The basis of language learning can be developed by working in pairs or in small teams; this new method can be aptly applied in primary school (Verreman, 2003; Narcy-Combes, 2014). This is learning led by communicating and discussing with individuals in the immediate environment. The entire above-mentioned practice and the development of linguistic skills are closely linked to the mission of the Lithuanian education as defined in the State Education Strategy 2013-2022 (2014); the main goal that is laid down in this strategy is “to provide every individual who relates himself/herself to Lithuania with the basics of independent and active life, to help them to continuously improve their abilities to become fully-fledged members in a democratic society who are active in a social, economic and cultural life” (p. 21). For an individual to be independent and active, they have to have good linguistic skills and a well-argued opinion. Besides, the issue of developing argumentation skills is also emphasized in the National Curriculum Framework of Lithuanian Language in Primary School (Bareikienė, Jakavonytė-Staškuvienė, Jonynienė and others, 2016, p. 11).This document states that a fourth grader (children 10-11 years) should be able to express opinion and to ground it with arguments; to speak with the goal of communication in mind, e.g. to tell a story in order to raise interest, to inform precisely, to explain, to describe in detail, to put forward arguments in order to persuade others. Therefore, in order to fulfil these expectations, the process of linguistic education should be organized in the primary school. Collaboration in pairs refers to situations when knowledge and understanding are developed collaboratively by sharing and exchanging information and differences of opinion. Collaboration based on shared problem solving and creative activity where other opinions are taken into account and advice is given plays a very important role (as stated in Common European Framework of Reference for Languages: Learning, Teaching, Assessment, 2018). In this article we will show the way primary schoolchildren develop language (L1) argumentation skills and reflect on the activity when working in pairs. [From the publication]