Charles Yang - The Problem of Exceptions

As Sapir once famously remarked, all grammars leak. How, then, does a child learner distinguish the systematic rules of their language from the exceptions, all in a few short years and without effective feedback? This central problem in language acquisition has important implications for the general theory of language and cognition, and potentially for the development of unsupervised natural language processing systems.  Reviewing case studies from phonology, morphology, and syntax, I suggest that the Tolerance Principle provides a simple and effective solution.