The research presented in this volume covers first language acquisition, second language acquisition, language heritage and language impairment. Papers in this collection use a variety of experimental methods, such as eye-tracking, elicitation tasks, production tasks administered off-line and untimed, transcriptions of spontaneous speech, production elicitation, Truth Value Judgement tasks, standardized tests and multiple choice tasks. The studies included in this book try to cover most of the methods used in first and second language acquisition in typical and atypical populations. This book will be useful for linguists, speech therapists, and psycholinguists working on first, second and impaired language acquisition.