# How to add rules to the lemmatizer?

**URL:** <https://support.prodi.gy/t/how-to-add-rules-to-the-lemmatizer/3896>\
**Category:** Uncategorized\
**Tags:** spacy, off-topic\
**Created:** [February 17, 2021, 5:52am UTC](https://support.prodi.gy/t/how-to-add-rules-to-the-lemmatizer/3896 "2021-02-17T05:52:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![thalish](https://sea2.discourse-cdn.com/flex020/user_avatar/support.prodi.gy/thalish/32/1642_2.png) [@thalish](https://support.prodi.gy/u/thalish)\
**Post date:** [February 17, 2021, 5:52am UTC](https://support.prodi.gy/t/how-to-add-rules-to-the-lemmatizer/3896/1 "2021-02-17T05:52:19Z")

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I'd like to find some documentation regarding how to tune the behavior of the spacy's lemmatizer (v2.2)

For example - Currently words like media and data get changed to medium/datum.

I'm interested in tweaking this to reflect how I want the lemmatizer to behave.

P.S - I am not interested in switching to a lookup based lemmatizer , I'm interested in tweaking the POS rule based lemmatizer behavior.

Could you please point me to any resources that explain how to do this?

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**Author:** ![honnibal](https://sea2.discourse-cdn.com/flex020/user_avatar/support.prodi.gy/honnibal/32/35_2.png) [@honnibal](https://support.prodi.gy/u/honnibal)\
**Post date:** [February 17, 2021, 11:27am UTC](https://support.prodi.gy/t/how-to-add-rules-to-the-lemmatizer/3896/2 "2021-02-17T11:27:44Z")

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Hi @thalish ,

The lemmatizer in v2.2 didn't really have a configurable API. In v3 the component is much better, although we're still working on end-to-end guides.

You should ask this type of question on the spaCy discussion forum, though, not here: [Discussions · explosion/spaCy · GitHub](https://github.com/explosion/spaCy/discussions)

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**Author:** ![thalish](https://sea2.discourse-cdn.com/flex020/user_avatar/support.prodi.gy/thalish/32/1642_2.png) [@thalish](https://support.prodi.gy/u/thalish)\
**Post date:** [February 17, 2021, 8:03pm UTC](https://support.prodi.gy/t/how-to-add-rules-to-the-lemmatizer/3896/3 "2021-02-17T20:03:29Z")

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Oops! Just realized this is a pure spacy question and not a good fit for this forum.

I've gone ahead and created this thread , looking forward to learning more about spacy3.0 [Custom spacy Lemmatizer · Discussion #7102 · explosion/spaCy · GitHub](https://github.com/explosion/spaCy/discussions/7102)