This study has investigated how teachers at a rural school and an urban school perceive the interplay between dialect, dialect levelling and linguistic norms in teaching. The researcher also observed four Swedish language lessons in grade 4 and 6 at each school. In addition, one lesson in each grade was observed in other subjects, such as mathematics, history, geography and home and consumer studies, resulting in a total of eight observed lessons. To explore the teachers’ perceptions, four semi-structured interviews were conducted with teachers who teach Swedish. The semi-structured interviews, in combination with participant observations, complemented each other well and contributed to strengthening, problematizing, and nuancing the findings. The results show that students’ spoken language varies between a Västerbotten dialect, a more standard variety of Swedish, and a form of language influenced by social media, including slang, abbreviations, informal chat language, and English words and expressions. It emerged that the teachers perceived the influence of social media on language as relatively strong, and that words becoming popular on social media spread quickly and become a natural part of students’ spoken language. The observations also revealed variations in how students’ spoken language was expressed depending on the teaching situation and context. Furthermore, the results show that different forms of dialect are still present in students’ speech through dialectal words and expressions, as well as features such as stress, prosody, and pronunciation. Signs of dialect levelling were also identified, as some students used a more standardized form of language in different situations and contexts.