tl;dr
Natural language processing is the branch of AI that lets a system read and interpret human language, in a document, an email, a chat message, and extract meaning from it.
In finance, NLP is what allows a system to pull the vendor name, amount, and due date off an invoice, interpret a contract clause, or answer a plain-language question about the numbers.
NLP is the layer that makes finance data queryable in the way people actually think about it. Instead of navigating a report builder, someone can ask what accounts receivable looked like last quarter and get a direct answer, because the system understands the question, not just the underlying schema.
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