True, there may be two language-processing systems, lexicon and syntax. However, could we not say more than that they are computationally and linguistically distinct? Where are they in the brain, why are they where they are, and how can their distinctness and functional properties be explained by biological principles? A brain model of language is necessary to answer these questions. One view is that two different types of corticocortical connections are most important for storing rules and their exceptions: short-range connections within the perisylvian language cortex and long-range connections between this region and other areas. Probabilities of neuroanatomical connections plus associative learning principles explain why different connection bundles specialize in rule storage versus exception learning. Linguistic issues related to language change and plural formation in German are addressed in closing.