Spacy -> Open source natural language processing library for python. Has one algorithm which can be used, which is the most efficient one.
NLTK -> Natural Language Toolkit is a very popular open source.
For most common NLP tasks, Spacy is much faster. NLTK has a variety of implementations.
Download english language library with spacy. Spacy needs to be installed.
$ python -m spacy download en
NLP -> text processing (natural language processing) Text data is unstructured. Example Use Cases: -> Classifying Emails as Spam vs Legitimate -> Sentiment Analysis of Text Movie -> Analyzing Trends from written customer feedback forms -> Understating text commands
Sometime before doing the nlp on text, a stemming is done to reduce the number of words. Another technique is Lemmatization. Lemmatization is looking at surrounding text to determine the text to reduce.