As much L2 as possible, as little L1 as necessary – this guiding principle has been widely accepted for instructed foreign language learning (e.g.Butzkamm & Caldwell, 2009). Proponents argue, e.g., that L1 use can support learning the L2. In contrast, there is the danger of teachers overusing the L1 and thus disadvantaging their learners. Prior studies found negative correlations between frequent L1 use and students’ L2 proficiency (Helmke et al., 2008). Thus,L2 teachers ought to decide deliberately in which situations and for what purposes they revert to the L1 (e.g., classroom management, support of individual learners). L2 teachers’use of the L1 in the L2 classroom can be explained by factors such as their L2 proficiency or beliefs (e.g., McMillan & Rivers, 2011). Studies investigating out-of-field L2 teachers, i.e. teachers who did not major in the L2, found that they use the L2 less frequently, have a lower L2 proficiency (Dörr, 2018), and feel insecure in using the L2 (Deters-Philipp, 2018).

The aim of the current study was to explore for the German context in which situations primary EFL (English as a foreign language) teachers use the L1 (German) and the L2 (English), and to analyze if a more frequent use of the L2 is positively correlated with teachers’ L2 proficiency. To this end, data was collected in 2017 through a computer-based survey among German primary teachers teaching EFL in year 4 (n = 844). L2 use was assessed through a four-point Likert scale comprising 16 Items on various classroom situations. Additionally, teachers in an open question described their L1 use in the EFL classroom. Finally, teachers self-assessed their L2 proficiency by dis-/agreeing to CEFR descriptors (Council of Europe, 2001).Findings indicate a great variation of situations in which teachers use the L1in the primary EFL classroom. As expected, results show that the L1 usecan be explained by the teachers’ L2 proficiency. The authors discuss aspects of ‘ideal’ use of L1 and L2 in primary EFL education. In doing so they argue target language use in the primary EFL classroom should be a central issue addressed in initial teacher education as well as continuous professional development.