The interactionist theory (Long, 1996), one of the most well-established frameworks within the field of second language acquisition (Gass & Mackey, 2007; García Mayo & Alcón Soler, 2012), maintains that communication among language learners greatly facilitates the acquisition of the language, especially when meaning is negotiated among them for mutual comprehension. More specifically, meaning negotiation among learners encourages them to modify their speech production and to provide and utilize corrective feedback, which, at the same time, can strengthen further learning. Working within this framework, the main goal of the present project is to document and describe in detail oral interaction among learners of English as a foreign language (EFL) in Primary Education in order to assess if they will be able to interact and negotiate meaning and linguistic form with their peers. A second goal is to analyze the effects of interactional feedback and the use of the first language (L1) on the learners’ interlanguage development. The analysis of these strategies (negotiation, interactional feedback and L1 use) will help us determine their potential impact on foreign language learning and provide pedagogical guidelines for foreign language teachers in primary education. In order to accomplish these objectives, we will investigate negotiation and corrective feedback strategies in young learners of EFL between the ages of 6 and 12 years while they complete communicative language tasks in school. The project will compare learners that follow two types of methodological approach: one group will be exposed to Content and Language Integrated Learning (CLIL) instruction while the other will be exposed to English as a Foreign Language (EFL) instruction. While CLIL and EFL approaches have been compared in various contexts, one critique has been that the most advanced learners are usually selected for CLIL instruction. The present project attempts to resolve this problem by collecting data from a school in which CLIL is gradually being implemented for the entire student body, while EFL is, at the same time, gradually disappearing. To summarize, the present project seeks to document and describe negotiation and corrective feedback strategies as well as L1 use by young learners of English, a population that has not been previously studied within an interactional perspective in the Spanish context. Moreover, the impact of these strategies on the acquisition of English will be analyzed. Finally, a database will be created and made accesible to other researchers in the field and pedagogical guidelines will be prepared to be used by English teachers in primary school, both in EFL and in CLIL contexts.