Natural Language Processing (NLP) assists computers with processing and understanding natural human language, such as speeches, tweets, and newspaper articles. NLP can range from counting the number of times a word appears in text to analyses that assess attitudes (e.g., positive, negative). NLP can be conducted on a variety of platforms, including the robust NLTK package in Python and several libraries in R.
For an introduction and hands-on experience using the NLTK in Python, DataCamp provides a free module as part of their NLP fundamentals course: https://www.datacamp.com/courses/natural-language-processing-fundamentals-in-python.
Additional information on the NLP packages in R can be found here: https://rpubs.com/lmullen/nlp-chapter, and an introduction to text-mining and word cloud creation can be found here: http://www.sthda.com/english/wiki/text-mining-and-word-cloud-fundamentals-in-r-5-simple-steps-you-should-know.