Natural Language Processing — Topic modelling (including latent Dirichlet allocation-LDA & analysis) and Sentiment Analysis

I have been working on NLP for some time now and thought that I would put together a list of tools & libraries that I normally use for various purposes such as topic modelling, sentiment analysis, named entity recognition etc. When dealing with a lot of text, as data scientists, we need to find order in the chaotic mix and find patterns that tell a story. Topic modelling and sentiment analysis helps makes this more achievable.