One well-known method of artificial intelligence for removing problematic aspects from unprocessed plain text data is natural language processing (NLP). It can be used to process the initial software requirements in order to accomplish objectives such as functional and non-functional requirement classification and prioritizing. To the best of our knowledge, there hasn’t yet been any research done to look into and compile how NLP is used in the field of Software Requirements Engineering (SRE). Thus, we explored the role of NLP in the context of SRE in this study. A Systematic Literature Review (SLR) was conducted on 41 papers that were published between 2002 and 2023. As a result, 17 current tools and 6 NLP techniques were recognized. In addition, the researchers recommended two algorithms and 11 tools. It has been determined that NLP methods and resources greatly aid in quickening the SRE procedure. Nonetheless, before implementing the intended NLP techniques, some manual tasks are still necessary for the basic plain text program.