An Introduction to Approximate String Matching
semanti.ca
semanti.ca
In more advanced applications, there's also the Kendall tau distance [2], Jensen-Shannon divergence [3], overlap coefficient [4], Jaccard index [5], any many more, which may prove significantly more precise (depending on your use case).
[1] https://en.wikipedia.org/wiki/Damerau–Levenshtein_distance [2] https://en.wikipedia.org/wiki/Kendall_tau_distance [3] https://en.wikipedia.org/wiki/Jensen–Shannon_divergence [4] https://en.wikipedia.org/wiki/Overlap_coefficient [5] https://en.wikipedia.org/wiki/Jaccard_index
Excellent implementation of these two and other edit distances are available as part of the jellyfish package https://pypi.org/project/jellyfish/
e.g. your September:SEP mapping will fail when encountering the token Sept, but Levenshtein will help you get this one right.