As educators turn to technology to supplement classroom instruction, the integration of natural language processing (NLP) into educational technologies is vital for increasing student success. NLP involves the use of computers to analyze and respond to human language, including students' responses to a variety of assignments and tasks. While NLP is widely used to deliver students with formative feedback, it can also be used to provide educators with information about task difficulty, students' individual differences, and student performance. In this chapter, we will first provide an overview of NLP, followed by a discussion of how NLP could be used to examine the learning process across a number of time points. Finally, we consider the future applications of NLP in the learning analytics domain. [This chapter is in: "Handbook of Learning Analytics--Second edition, pp. 46-53, Society for Learning Analytics Research, Vancouver, BC.]