Words and Rules: The Ingredients of Language is a 1999 popular linguistics book by Steven Pinker about regular and irregular verbs.

It has been popularly contextualized within the so-called "Past-Tense Debate," which was sparked by Rumelhart and McClelland's 1986 connectionist model of the production of regular and irregular verbs.

In his book, Pinker "tries to illuminate the nature of language and mind by choosing a single phenomenon and examining it from every angle imaginable.

Most of the book examines studies conducted on the form and frequency of grammatical errors (such as overgeneralization in past-tense formation) in English (and to a lesser extent in German) as well as the speech of brain-damaged persons with selective aphasia.

He writes that words are either stored directly with their associated meanings in the lexicon (or "mental dictionary") or are constructed using morphological rules.