We also restrict ourselves to a segmental representation of the phonology. Our German phonological segment inventory is taken from CELEX (Baayen et al., 1993, 1995) and uses the SAMPA machine-readable phonetic alphabet (Wells, 1987).
As one of us has shown in earlier work (Cahill 1993), the step from representing structures with segments to representing the same structures with full feature sets at each point in the tree is relatively simple. We have not taken that step here because it would not add anything to most of the present analysis but it would make our DATR code much harder to read. Use of featural representation would, however, make it easier and more elegant to state certain phonological alternations in German such as final consonant devoicing. The same applies to the morphophonological alternations vowel lengthening and umlaut.
We assume throughout that a fully inflected form is simply a string of phonological segments. For our present purposes, there is no need for the implicit tree structure of phonological objects to be made manifest in the output. It is, however, a simple task to modify the rules we give so as to make the tree structure explicit in the way inflected forms are encoded.