This book examines how the underlying linguistic competence of second language (L2) learners is constrained by the same universal principals governing natural language. It is assumed that there is an innately given universal grammar (UG) which constrains L1 grammars, limiting the kinds of hypotheses that L1 acquirers entertain about the nature of the language they are acquiring. Assuming this is correct, the question arises as to whether UG also constrains grammars in non-primary language acquisition. Eight chapters discuss the following: (1) "Universal Grammar and Language Acquisition" (e.g., parameters of UG and UG access); (2) "Principles of Universal Grammar in L2 Acquisition" (e.g., UG and the logical problem of L2 acquisition and alternative accounts); (3) "The Initial State" (e.g., a grammar as the initial state and assessing initial state hypotheses); (4) "Grammars Beyond the Initial State: Parameters and Functional Categories" (e.g., global and local impairment and parameter setting and resetting); (5) "The Transition Problem, Triggering and Input" (e.g., parsing and parameter setting); (6) "Morphological Variability and the Morphology/Syntax Interface" (e.g., surface versus abstract morphology and methodological considerations); (7) "Argument Structure" (e.g., lexical entries and mapping from lexicon to syntax); and (8) "Ultimate Attainment: The Nature of the Steady State" (e.g., convergence versus divergence and age effects on ultimate attainment). (Contains approximately 450 references.) (SM)