Previous research has shown that L2 students have difficulties producing and even recognising sounds that do not exist in their mother tongue. It has also been concluded that accented speech not only compromises intelligibility but also makes the listener negatively biased towards the speaker. The present study explores how proficient Swedish students are in producing the speech sounds /dʒ/, /j/, /v/, /w/, /ʃ/and /tʃ/, of which /dʒ/, /w/ and /tʃ/do not exist in Swedish. In addition, it explores whether their pronunciation of these sounds improves after a brief pronunciation lesson, if this improvement is lasting and whether they tend to learn the pronunciation of words as separate units or are able to generalise the rules of pronunciation and appropriately apply them. It also investigates whether a difference in the structure of the pronunciation lesson affects the students’ results. The study revealed that the students do have difficulties with correctly producing in particular /tʃ/, /dʒ/ and /j/. More specifically, they tended to confuse /dʒ/ and /j/ whereas many students appeared to have been unaware that /tʃ/ exists and used the /ʃ/-sound instead, which exists in Swedish. After the pronunciation lesson, however, the students significantly improved their pronunciation. This improvement was shown to be lasting and the students were generalising rules rather than learning words as separate units. What the study failed to show was a significant difference in results caused by a difference in the structure of the pronunciation lesson.