Bear, J. (1988). Morphology with two-level rules and negative rule features. In Coling Budapest 1988 Volume 1: International Conference on Computational Linguistics.
Two-level phonology, as currently practiced, has two severe limitations. One is that phonological generalizations are generally expressed in terms of transition tables of finite-state automata, and these tables are cumbersome to develop and refine. The other is that lexical idiosyncrasy is encoded by introducing arbitrary diacritics into the spelling of a morpheme. This paper describes how to use phonological rules instead of transition tables, and describes a more elegant way of expressing phonological irregularity than with arbitrary diacritics, making use of the fact that generalizations are expressed with rules instead of automata.