The field of natural language processing (NLP), which aims to represent and analyze human language digitally, has recently attracted much interest. Machine learning has found several uses, including translation, spam filtering, data mining, stigmatization, medicine, and answering questions online. After introducing the background and development of NLP, it breaks down into four distinct periods by describing the various stages of NLP and the building blocks of Natural Language Generation (NLG). The numerous applications of NLP, current trends, and problems are then presented, the state of the art in great depth. At the end of the paper, it explores several existing NLP datasets, models, and assessment measures