An English lingua franca seems to be emerging in the ten ASEAN countries, and this paper investigates features of the pronunciation of this lingua franca. Twenty speakers, two from each of the ASEAN countries, were recorded while they were conversing in groups of three or four people, all from a different country. The speech that they used is analysed to identify shared features of pronunciation, especially to evaluate the effect that these features have on intelligibility, and it is argued that some of their shared non-standard features actually enhance intelligibility. Finally, some of the misunderstandings that occurred are analysed to determine the extent to which pronunciation played a part, and it is found that only those features of pronunciation not shared by speakers from other ASEAN countries resulted in a break-down in communication. Copyright © 2006 The Authors. Journal compilation © 2006 Blackwell Publishing Ltd.