This book reports the results of an extensive study of slips of the tongue produced by foreign language (L2) learners at different levels of proficiency. Thus, it provides new data which can be used to test current monolingual models of speech production and to further the development of bilingual speech production models. Moreover, it offers a new approach to the study of second language acquisition. The book contains a detailed survey of the findings of L1 slip research, including studies of slips produced by child L1 learners. It systematically compares these findings to those of the current L2 study and relates them to recent monolingual and bilingual models of speech production and to several cognitive models of second language acquisition. Special features of the book are its emphasis on methodological problems and the inclusion of the complete L2 corpus of 2000 slips of the tongue. It is expected that the book will be of interest to researchers and advanced students in the areas of speech production and second language acquisition, and particularly to those who would like to test their own hypotheses using the L2 data.Summary of the contents of the book. The book provides an overview of the key findings in L1 slip research. It relates L1 findings to monolingual speech production models. It gives a detailed survey of studies of slips produced by children. It presents an up-to-date review of bilingual speech production models. It discusses recent cognitive models of second language acquisition. It gives a detailed description of an extensive research project on slips of the tongue produced by Dutch learners of English. The L2 slip corpus is tape-recorded. It discusses methodological problems in L1 slip research. It systematically compares the L1 findings to those of the L2 slip project. It relates the findings to monolingual and bilingual models of speech production and to cognitive models of second language acquisition. It makes the data available in the appendix.