A Compensation Model is proposed to help explain the difference between child and adult language acquisition in terms of different cognitive modules and theories. In this model, two assumptions are made: (1) existence of two different cognitive modules (language-specific and general-cognition) in the mind, and (2) the independent and interactive roles of these two modules, each responsible for each aspect of learning, with the higher level compensating for the lower. The model is descriptive in that it incorporates findings reported in current second-language research, and explanatory in that it explains the logical and developmental problems of child and adult language acquisition. In addition, it is predictive because it can predict why children are better language learners than adults in terms of ultimate attainment, why native language and language learning strategies play critical roles in adult rather than child language acquisition, and why there are variables degrees of attainment in adult language acquisition. Contains 69 references. (MSE)