A Phonological Rule Tester The design and implementation of a system to alleviate the problem of rule evaluation for the linguist in the area of phonology are presented. It permits the user to define, on-line, sets of rules statable within the framework presented in The Sound Patterns of English by Chomsky and Halle, 1968, to define phonemes as bundles of specified distinctive features, to define data as strings of phonemes with associated grammatical structure, to test the effect of applying rules to the data, and to store both the definitions and results. The rule application facility described in detail was implemented by translating linguistic rules to rules in FLIP, a format-directed list processor embedded in LISP. This made the system construction easy while providing sophisticated capabilities for the linguist. The system is written in BBN LISP on the Scientific Data System 940 computer and is designed to be used on-line in interactive fashion, with control returned to the user after each command is executed. CACM November, 1968 Borrow, D. G. Fraser, J. B. phonology, rule tester, linguistics, transformational grammar, LISP, format-directed list processing, on-line systems 3.42 4.13 4.22 CA681108 JB February 21, 1978 2:41 PM 1659 5 1671 1671 5 1671 1671 5 1671 1671 5 1671 1225 6 1671 1265 6 1671 1350 6 1671 1671 6 1671 1697 6 1671