This study set out to investigate the relationship between perception and production of English / tʃ, dʒ/ and / ʒ / by native speakers of Swedish learning English in secondary school. The aim was to find out if Flege’s Speech Learning Model (SLM) (1995) and Major’s Ontogeny Phylogeny Model (OPM) (2001) are suitable to describe young learners’ L2 phonological attainment. To test perception, an identification task containing Nonwords with target sounds in initial, medial, and final position was constructed and tested on 17 school students. Three speaking tasks were carried out to test the participants’ production of the phonemes in initial, medial and final position. All participants also completed a questionnaire with questions regarding exposure and motivation. Six students were chosen for deeper analysis. The results show that both the SLM and the OPM can be used to describe young learners L2 phonology acquisition. Similar sounds were found to be harder to produce and more affected by L1 transfer, which corroborates both the SLM and the OPM. Marked sounds were affected more by universals, which was suggested by the OPM. Desire to have a native accent and reported use of the L2 seems to have effect on L2 phonology acquisition, as well. However, the relationship between all these factors is complex and the results from this study are merely suggestive.