To develop a full understanding of how phonetic learning takes place, a consideration of errors seems essential. However, attending only to linguistic influences on acquisition cannot advance knowledge about L2 pronunciation beyond what is already known. In that regard, promising developments in the field include Best's perceptual assimilation model (Best and Tyler, 2007) and Flege's speech learning model (Flege, 1995), both of which devote attention to the perception of non-L1 speech sounds. Both also diverge from traditional linguistic approaches such as CAH in that they do not treat...