Words and rules

The vast expressive power of language is made possible by two principles: t he arbitrary sound-meaning pairing underlying words, and the discrete combi natorial system underlying grammar. These principles implicate distinct cog nitive mechanisms: associative memory and symbol-manipulating rules. The di stinction may be seen in the difference between regular inflection (e.g., w alk-walked), which is productive and open-ended and hence implicates a rule , and irregular inflection (e.g., come-came, which is idiosyncratic and clo sed and hence implicates individually memorized words. Nonetheless, two ver y different theories have attempted to collapse the distinction; generative phonology invokes minor rules to generate irregular as well as regular for ms, and connectionism invokes a pattern associator memory to store and retr ieve regular as well as irregular forms. I present evidence from three disc iplines that supports the traditional word/rule distinction, though with an enriched conception of lexical memory with some of the properties of a pat tern-associator Rules, nonetheless, are distinct from pattern-association, because a rule concatenates a suffix to a symbol for verbs, so it does not require access to memorized verbs or their sound patterns, but applies as t he 'default', whenever memory access fails. I present a dozen such circumst ances, including novel, unusual-sounding, and rootless and headless derived words, in which people inflect the words regularly (explaining quirks like Pied out, low-lifes, and Walkmans). A comparison of English to other langu ages shows that contrary to the connectionist account, default suffixation is not due to numerous regular words reinforcing a pattern in associative m emory, but to a memory-independent, symbol-concatenating mental operation.