The aim of this article is to review the psycholinguistic research on second language (L2) self-repair to date with particular attention to the relevance of this field for L2 production and acquisition. The article points out that W. J. M. Levelt's (1989Levelt's ( , 1993Levelt's ( , 1992 and W. J. M. Levelt et al.'s (in press) perceptual loop theory of monitoring can be adopted for monitoring in L2 speech as well. It is also argued, however, that this theory needs to be complemented with recent research on consciousness, attention, and noticing in order to account for mechanisms of error detection in L2.Speech errors have traditionally been seen as exposures of the underlying language-formulating machinery and, indeed, taken together with the study of hesitation devices and pauses, it is the analysis of repair mechanisms that can provide us with the most direct information about the psychological and linguistic processes at work in first language (L1) and second language (L2) speech production and communication. Thus, the phenomena of self-repair and monitoring in the speech of both L1 and L2 speakers have been of great interest to applied linguists, sociolinguists,