The main goal of this research in this book is to improve automatic pronunciation evaluation of reading-aloud and shadowing based on speech technology for Computer-Assisted Language Learning (CALL) systems. We first investigate the effects and problems of Maximum Likelihood Linear Regression (MLLR) speaker adaptation when used in pronunciation evaluation of reading-aloud. Following the analysis, we propose a novel method, Regularized Maximum Likelihood Regression (Regularized-MLLR) adaptation, to solve the problem of the adverse effects of MLLR adaptation. This method uses a group of...