Stemming.md (1177B)
1 # Stemming 2 3 **Source:** https://www.nltk.org/howto/stem.html 4 5 **Definition:** Stemming is an NLP approach to simplify terms that convey the same meaning into the same form by stripping affixes. 6 7 ## Examples With Porter Stemmer 8 9 caresses -> caress 10 caressing -> caress 11 stemming -> stem 12 stem -> stem 13 flies -> fli 14 flying -> fli 15 16 NOTE: Porter stemmer is the most popular stemmer for English 17 18 ## Usage 19 20 In practice, stemming is very useful in English for keyword matching because it is closer to capturing the meaning of words, making keyword searches more representative of semantics. 21 22 Additionally, in practice, it can be more performant than lemmatization. 23 24 ## Limitations 25 26 Different languages employ different approaches to word tense and combination such that the generalization of stemming is generally limited to a specific language, and there may not be a simple approach that can be applied to all languages (even individually). 27 28 Additionally, terms in English like 'news' are changed to 'new' (using Porter stemming) which can result in lost meaning. Such limitations don't necessarily apply to lemmatization which uses a dictionary based approach, but tends to be slower.