The study explores the psycholinguistic processes underlying L2 self-repair behavior bymeans of analyzing the timing of various types of self-corrections found in the speech of 30Hungarian speakers of English at three levels of proficiency (pre-intermediate,upper-intermediate, and advanced). The paper discusses the relevance of timing data for theexisting models of speech monitoring and examines how the level of proficiency of L2 learnersaffects the speed of error detection and the execution of correction. The results obtained indicatethat the perceptual loop theory and the activation spreading theory of monitoring both rightlyassume that monitoring involves the same mechanisms as speech comprehension. The analysis ofthe timing data reveals that corrections of pragmatically inappropriate lexical choice havedetection times very similar to those of lexical errors. This may be regarded as indirect evidencefor the claim that lexical entries in the mental lexicon also contain specifications concerning theirpragmatic value. The results show that the level of proficiency of the participants affects the timenecessary for the lexical, grammatical, and phonological encoding of the repair, which is causedby the difference in the degree of automaticity of these mechanisms at various stages of L2development.