😊 😬 Free sentiment analysis tool for social media in English, French and Spanish

The principles followed by the tool are described in this academic publication about Umigon, published in the anthology of the Association fo Computational Linguistics. The tool follows these steps:

1. check on the length of the text: if it is just a couple of words short, it will not be classified
2. removal of urls, removal of content in quotes, normalization of apostrophs
3. two versions of the text are established: one where all the accents and special characters are removed, and one where they are retained. All the following steps will apply to both versions of the text.
4. check on emojis, emoticons and onomatopeia. Do not preprocess your text to remove them, they provide useful information on sentiment!
5. check on hashtags, if any
6. decomposition of the text in n-grams up to four-grams
7. for each n-gram:
   • skip it if it belongs to a pre-established list of stop words
   • check for repeated characters and remove them as necessary (yeeeahhh! becomes yeah!)
   • check if the n-gram is contained in the pre-established list of potentially positive words. If so, the corresponding rule is applied. Most often the rule is as simple as "a positive word gives a positive sentiment to the text", but more complex rules are also included of course.
   • check if the n-gram is contained in the pre-established list of potentially negative words. Same logic applies
8. final checks: detection of moderators in the sentence ("but", "however", "even if", etc.). Positive or negative values placed before or after these moderators are kept or get deleted.
9. final decision following complex rules, based on the results of the previous steps.

Some tools provide a scoring to express the strength of the sentiment: a large value for a very positive sentiment, and a very low value for a negative sentiment. Zero represents a neutral sentiment. In my experience, these scorings are not super reliable, except for the obvious cases. "Horrible" will score really low, and "wonderful" will score really high. But in the middle, things are less straightforward and the scorings are much harder to interpret - I would not advise to rely on them. A more promising road would be to introduce emotions to tease out the finer nunances of sentiment, beyond the positive / neutral / negative categories. Drop an email at admin@clementlevallois.net if you are interested in this direction of research.

This tool identifies subjective markers of sentiment, NOT positive or negative factual statements. To give an example:

• "This country is at war" -> it is classified as NEUTRAL, even if a country at war is "objectively" or "factually" not a positive thing.
• "War is horrible :(" -> it is classified as NEGATIVE because the term "horrible" and the emoji are subjective markers of a negative sentiment.
• "War of the sexes is an exciting research topic!" -> it is classified as POSITIVE because the term "exciting" is a subjective marker of a positive sentiment.