Integrating NLP with Solr improves search quality by normalizing language, identifying entities, and expanding related terms. Instead of treating words as isolated tokens, NLP lets Solr recognize that “run,” “running,” and “ran” refer to the same concept, or that “Paris” may refer to a location entity. This results in higher recall, better matching, and more contextually relevant results.

For reference, a detailed study on this approach is available below, analyzing the impact of NLP techniques on Solr’s search relevancy.

https://www.diva-portal.org/smash/record.jsf?pid=diva2%3A1577525&dswid=-8621