This small-scale study examines English foreign language (EFL) teaching in Danish upper secondary education (gymnasium), investigating the dynamics of language use among pupils in Danish upper secondary English classes. Through direct classroom observations, we explore how pupils engage with the language, particularly focussing on the prevalence of Danish versus English speech. We aim to explore how much English language spoken input upper secondary pupils receive and how much English language output pupils produce. Our findings reveal a notable tendency among pupils to predominantly use Danish during English classes or opting for silence altogether. In terms of input, we found that English is widely used by teachers in class, however, they switch to Danish when teaching grammar. This phenomenon underscores an interplay of cultural, motivational, and personal factors influencing pupil language choice and proficiency development. Our discussion considers the underlying reasons behind this linguistic behaviour, as well as the challenges and implications for language learning and teaching in Danish upper secondary education. Furthermore, we look at similar phenomena in a broader European context. We discuss the potential impact of classroom environment and pupil attitudes on language use patterns, offering insights to enhance English language acquisition and communication skills among pupils. By addressing the observed disparities between language instruction and pupil language output, this study contributes to an understanding of language learning dynamics within the Danish upper secondary context.