This article sets out to examine teacher perceptions of letter learning in literacy programmes for L2-adults with limited earlier schooling, as demonstrated in their teaching. The theoretical frame is taken from New Literacy Studies, with literacy perceived as socially shared and organised. The study draws on occasions during lesson observations where teachers addressed the issue of coding and decoding of letters. Findings suggest that these teachers follow patterns that build on assumptions and traditions with roots in the teaching of L1 children and use the material that they have at hand. The teachers’ prosodic knowledge in relation to letters and spelling was insufficient. We argue that when teachers are not aware of the phonetic and phonological challenges facing adult L2 learners, they may not give students enough support in their development of early literacy skills. Although explicit letter teaching represents only a small part of overall teaching, if teachers miss out on phonetic and phonological knowledge, they may not be able to identify difficulties for students and may even create unnecessary stumbling blocks for them. We conclude that there is a strong need for the development of basic literacy education for L2-adults to include both teacher knowledge and teaching aids.