How are corrections in a text counted?

For every paragraph, Fairlingo checks how much text the revisor added and removed. To do this, we use the Levenshtein distance, which is widely used in linguistics to determine the difference between two sequences. Specifically, the minimum number of edits to change one string into another. We've listed the edits below. These edits result in a certain total, and that's the number that decides the number of points (and money) that are ultimately deducted.