Abstract The aim of this study is to investigate the effect of familiarity with Brazilian-accented English (L2) in the intelligibility of speech samples when judged by native English listeners. Speech samples were collected from five native Brazilian Portuguese individuals from Southern Brazil, with a pre-intermediate level of proficiency in English. Following a Complex Dynamic Systems account (De Bot et al., 2007), this is a longitudinal study in which a group of four British listeners participated in weekly intelligibility transcription tasks, administered over the course of five weeks. This group was comprised of individuals who had recently arrived in Brazil. Results suggest that familiarity with a speaker’s L1 and accented-L2 has an effect on the intelligibility of what is heard. From the perspective of Complex Dynamic Systems, we argue that there is an alteration of a listener’s perception of his/her own language system due to exposure to it as an L2.