The study of second language (L2) speech production has been informed by research in a number of areas, including phonological theory, acoustic phonetics, and articulatory phonetics. A synthesis of the research in these areas is presented in this paper. First, early theories about ‘foreign accents’ that have continued to influence current research are discussed, including the Contrastive Analysis Hypothesis and interlanguage. Next, we turn to the acquisition of consonants and vowels, which has been the subject of both experimental and theoretical investigations. The last section examines the acquisition of suprasegmental structure, such as syllables, phonotactics, and prosodic position. Several theories that elucidate the relative contributions of first language transfer and universal markedness are presented, such as the Markedness Differential Hypothesis and Optimality Theory. Both phonetic and phonological aspects of L2 production are considered in light of data from learners at all stages of language acquisition, from cross‐language speech production studies which may reflect the initial state of language learning to proficient L2 speakers.