I recently learned about Karen Sparck Jones who died in 2007. She did not have an obituary in The NY Times, though clearly she should have and now the Times is making up for it.
Some noteworthy quotes about her:
When most scientists were trying to make people use code to talk to computers, Karen Sparck Jones taught computers to understand human language instead.
She wanted to figure out how to program a computer to understand words that could have many meanings (for example “field”) and set about programming a massive thesaurus.
In 1964, Sparck Jones published “Synonymy and Semantic Classification,” which is now seen as a foundational paper in the field of natural language processing.
In 1972, she introduced the concept of inverse document frequency, which counts the number of times a term is used in a document in order to determine the term’s importance; it, too, is a foundation of modern search engines.