Thanks for reaching out!
We already have a lemmatization feature implemented under the name of
ignorePlurals. As of today we don’t support verbs, only nouns. This may or may not change in the future, today we think that also handling verbs may create too much noise in the results.
As of stemming, we don’t plan on implementing it. Our stance is that stemming is too unoredictable because of how it relies on general rules rather than a dictionary. Because of this, proper nouns or brands may be altered whereas they should not.
Don’t hesitate if you have more questions.