This paper starts by recognising that, in general, pronunciation is the least successfully taught of the second language skills, and suggesting this indicates a need for a better theoretical framework within which teachers can understand and facilitate learners' acquisition of L2 pronunciation. Structural-generative theory, which has been dominant in phonology for some time, has limited application in this domain. However, applying the principles of Cognitive Phonology may lead to improved results. It then reviews the basic Cognitive Phonology principle: 'the signifier is a concept', and explains how the literacy bias (the tendency of those literate in the alphabetic script to believe that speech is a string of discrete phonemes) makes this principle more difficult to grasp than the very similar but far more widely understood principle that the signified is a concept. Discussion continues to consider implications of this idea for language teachers: phonemes, and other units of phonology, are not real things but abstract concepts. Teaching pronunciation thus involves facilitating concept formation. The paper then moves to consider some implications for theory of the observation that the concept of phoneme is derived from prior understanding of words and other larger units of phonology. It concludes by suggesting there may be productive parallels between the arguments presented here regarding the relationship between words and phonemes, and arguments advanced by Construction Grammar in regard to the relationship between lexis and grammar, whose implications for second language teaching are explored by other papers in this volume.