Summary (Project 4) Acquired disorders of language, such as aphasia, can have devastating effects on an individual’s quality of life and livelihood. Up to 2,000,000 people in North America have aphasia making it a significant public health concern. The goal of Project 4 is to improve our ability to diagnosis, treat, and predict recovery from aphasia using quantitative and theoretical models of how language works and how it is implemented in the brain. As part of the Center for the Study of Aphasia Recovery (C-STAR), this project has three specific aims: (1) to apply our MPT model to treatment outcome evaluation and recovery prediction, (2) to extend our quantitative and neural model of word production, and (3) to extend our theoretical scope to include syntax. Although Project 4 has a bit more theoretical slant that the other three Projects, we have made a concerted effort to also emphasize the clinical application of the project.