This paper presents a set of mathematical and computational tools for manipulating and reasoning about regular languages and regular relations and argues that they provide a solid basis for computational phonology. It shows in detail how this framework applies to ordered sets of context-sensitive rewriting rules and also to grammars in Koskenniemi's two-level formalism. This analysis provides a common representation of phonological constraints that supports efficient generation and recognition by a single simple interpreter. 1.

We are working on a module for morpholgical analysis and generation, which is based upon Two-Level Morphology(TLM). This module is part of a larger project to improve an existing real world application. The purpose of this paper is to enlighten our approach to some problems or holes we encountered with the original TLM-system described by Koskenniemi. The requirements of the system are amongst others: ffl Enabling to exclude or compel combinations of prefixes and suffixes on the same wordform. ffl Providing an elegant way to add compound words to the lexica. ffl The generation should start from the canonical form and some supplied lexical features instead of starting from a concatenation of lexical morphemes, that the user has composed beforehand. 1