I'm already familiar with a lot of the technical tools from another more engineering-oriented class, e.g., Natural Language Processing (6.864 at MIT). Will I learn much from this class?

There is indeed overlap between 9.19: Computational Psycholinguistics and more traditional Natural Language Processing (NLP) classes. However, the focus of 9.19 is very different: we use NLP tools to study how humans comprehend, produce, acquire, and represent language. This difference in focus means that 9.19 is highly complementary to most NLP classes: it will deepen your understanding of the technical tools, and enrich your overall picture of how these tools can be applied. If you are interested in the science of language processing in the human mind, then you will very likely find that what we cover in 9.19 is not overly redundant with what is covered in other NLP classes. (Keep in mind also that each of the technical tools & approaches is something that many researchers spend years on developing and studying, so you are unlikely to have a comprehensive understanding after just one or two classes.) Since I started teaching 9.19 in 2017, many students have taken it after taking a more standard NLP class and have reported positive experiences.