Nowadays, with the increasingly pervasive advent of the digital world, we are inundated with large amounts of data in text format relating to many everyday contexts. One important part of this data concerns user reviews of products and services. Analysing this large information content with machine learning algorithms can provide very useful information for companies and vendors to make improvements. This type of text analysis with machine learning belongs to the branch of Natural Language Processing (NLP) and more specifically to the branch of Sentiment Analysis. As far as sentiment analysis is concerned, there are many methods to carry out this kind of analysis in literature.